Science.gov

Sample records for evaluating forest growth

  1. Application of the Forest Vegetation Simulator in evaluating management for old-growth characteristics in southwestern mixed conifer forests

    Treesearch

    Claudia M. Regan; Wayne D. Shepperd; Robert A. Obedzinski

    1995-01-01

    We used the Forest Vegetation Simulator (FVS) and GRAFM graphics display to investigate conditions associated with the stability of an old-growth stand and to evaluate the potential for two managed stands of contrasting but representative conditions to develop structures similar to the old-growth stand. Simulations indicate that the example old-growth stand can retain...

  2. A computerized tree growth projection system for forest resource evaluation in the lake states

    Treesearch

    Allen L. Lundgren; Burton L. Essex

    1978-01-01

    A computerized tree growth projection system has been developed for the Lake States Region as part of a larger Forest Resources Evaluation Program (FREP). Incorporating data from more than 1500 permanent growth plots throughout the Lake States, this system projects tree growth, mortality, regeneration, and removals in stands with any mixture of tree species and sizes,...

  3. Evaluation of forest trees growth after sewage sludge application

    NASA Astrophysics Data System (ADS)

    Vaitkutä--, Dovilé; Balträ--Naitä--, Edita; Booth, Colin A.; Fullen, Michael A.; Pereira, Paulo

    2010-05-01

    Sewage sludge is extensively used in forest to improve soil properties. It is expected that sewage sludge rich in phosphorus, nitrogen and organic material enhance the germination of tree seedlings in poor soils. In Lithuania, the deforested soils are highly acid, and have a lack of nutrients, especially in exploited peat areas. Sewage sludge from industry contains beneficial components for the soils (such as organic matter, phosphorus, nitrogen, calcium, magnesium, etc.). However, it is also rich in heavy metals, especially Cd, Pb, Cu and Zn. High heavy metals concentrations in soil can be phytotoxic and cause reduced plant growth or plant death. The main objectives of this research was to determine the influence of industrial sewage sludge in the forestry and to highlight the idea that industrial sewage sludge containing metals does not favour development of birch and pine trees. The study was performed in Taruskos experimental plot in Panevezys region (Lithuania), amended with industrial sewage sludge ten years ago was afforestated with birch and pine seedlings. In order to observe the effects of the amendment in accumulation the mentioned metals and tree growth we collected data from trees in amended plot and control plot. The results showed that soil parameters were improved in the amended plot, in comparing with control site (higher pH, organic matter and cation exchange capacity). However, the growth of investigated trees was slower (e.g. birch roots, shoot, stem and leaves biomass was 40, 7.4, 18.6, 22% smaller than in control site. In pine case: 30, 1.2, 17, 36%, respectively; the stem height of birch was 16% and pine - 12% smaller than in control site). This reduced growth can be related with heavy metals concentration load on soil and accumulation in trees. Cu and Cd concentrations were higher in soil amended with sewage sludge comparing with control site (60 and 36%, respectively). Also, in contaminated trees Cu and Cd concentrations were higher (Cu

  4. Old growth in northwestern California national forests.

    Treesearch

    Debby Beardsley; Ralph. Warbington

    1996-01-01

    This report estimates old-growth forest area and summarizes stand characteristics of old growth in northwestern California National Forests by forest type. Old-growth definitions for each forest type are used.

  5. Application of a Hybrid Forest Growth Model to Evaluate Climate Change Impacts on Productivity, Nutrient Cycling and Mortality in a Montane Forest Ecosystem

    PubMed Central

    Seely, Brad; Welham, Clive; Scoullar, Kim

    2015-01-01

    Climate change introduces considerable uncertainty in forest management planning and outcomes, potentially undermining efforts at achieving sustainable practices. Here, we describe the development and application of the FORECAST Climate model. Constructed using a hybrid simulation approach, the model includes an explicit representation of the effect of temperature and moisture availability on tree growth and survival, litter decomposition, and nutrient cycling. The model also includes a representation of the impact of increasing atmospheric CO2 on water use efficiency, but no direct CO2 fertilization effect. FORECAST Climate was evaluated for its ability to reproduce the effects of historical climate on Douglas-fir and lodgepole pine growth in a montane forest in southern British Columbia, Canada, as measured using tree ring analysis. The model was subsequently used to project the long-term impacts of alternative future climate change scenarios on forest productivity in young and established stands. There was a close association between predicted sapwood production and measured tree ring chronologies, providing confidence that model is able to predict the relative impact of annual climate variability on tree productivity. Simulations of future climate change suggest a modest increase in productivity in young stands of both species related to an increase in growing season length. In contrast, results showed a negative impact on stemwood biomass production (particularly in the case of lodgepole pine) for established stands due to increased moisture stress mortality. PMID:26267446

  6. Application of a Hybrid Forest Growth Model to Evaluate Climate Change Impacts on Productivity, Nutrient Cycling and Mortality in a Montane Forest Ecosystem.

    PubMed

    Seely, Brad; Welham, Clive; Scoullar, Kim

    2015-01-01

    Climate change introduces considerable uncertainty in forest management planning and outcomes, potentially undermining efforts at achieving sustainable practices. Here, we describe the development and application of the FORECAST Climate model. Constructed using a hybrid simulation approach, the model includes an explicit representation of the effect of temperature and moisture availability on tree growth and survival, litter decomposition, and nutrient cycling. The model also includes a representation of the impact of increasing atmospheric CO2 on water use efficiency, but no direct CO2 fertilization effect. FORECAST Climate was evaluated for its ability to reproduce the effects of historical climate on Douglas-fir and lodgepole pine growth in a montane forest in southern British Columbia, Canada, as measured using tree ring analysis. The model was subsequently used to project the long-term impacts of alternative future climate change scenarios on forest productivity in young and established stands. There was a close association between predicted sapwood production and measured tree ring chronologies, providing confidence that model is able to predict the relative impact of annual climate variability on tree productivity. Simulations of future climate change suggest a modest increase in productivity in young stands of both species related to an increase in growing season length. In contrast, results showed a negative impact on stemwood biomass production (particularly in the case of lodgepole pine) for established stands due to increased moisture stress mortality.

  7. Acid deposition effects on forest composition and growth on the Monongahela National Forest, West Virginia

    Treesearch

    P.E. Elias; J.A. Burger; M.B. Adams

    2009-01-01

    The northern and central Appalachian forests are subject to high levels of atmospheric acid deposition (AD), which has been shown in some forests to negatively impact forest growth as well as predispose the forest system to damage from secondary stresses. The purpose of this study was to evaluate the possible contribution of AD to changes in composition and...

  8. A new method for evaluating forest thinning: growth dominance in managed Pinus resinosa stands

    Treesearch

    John B. Bradford; Anthony W. D' Amato; Brian J. Palik; Shawn. Fraver

    2010-01-01

    Growth dominance is a relatively new, simple, quantitative metric of within-stand individual tree growth patterns, and is defined as positive when larger trees in the stand display proportionally greater growth than smaller trees, and negative when smaller trees display proportionally greater growth than larger trees. We examined long-term silvicultural experiments in...

  9. The importance of phenology for the evaluation of impact of climate change on growth of boreal, temperate and Mediterranean forests ecosystems: an overview.

    PubMed

    Kramer, K; Leinonen, I; Loustau, D

    2000-08-01

    An overview is presented of the phenological models relevant for boreal coniferous, temperate-zone deciduous and Mediterranean coniferous forest ecosystems. The phenology of the boreal forests is mainly driven by temperature, affecting the timing of the start of the growing season and thereby its duration, and the level of frost hardiness and thereby the reduction of foliage area and photosynthetic capacity by severe frost events. The phenology of temperate-zone forests is also mainly driven by temperature. Since temperate-zone forests are mostly mixed-species deciduous forests, differences in phenological response may affect competition between tree species. The phenology of Mediterranean coniferous forests is mainly driven by water availability, affecting the development of leaf area, rather than the timing of phenological events. These phenological models were subsequently coupled to the process-based forest model FORGRO to evaluate the effect of different climate change scenarios on growth. The results indicate that the phenology of each of the forest types significantly affects the growth response to a given climate change scenario. The absolute responses presented in this study should, however, be used with caution as there are still uncertainties in the phenological models, the growth models, the parameter values obtained and the climate change scenarios used. Future research should attempt to reduce these uncertainties. It is recommended that phenological models that describe the mechanisms by which seasonality in climatic drivers affects the phenological aspects of trees should be developed and carefully tested. Only by using such models may we make an assessment of the impact of climate change on the functioning and productivity of different forest ecosystems.

  10. Exploring Old Growth Forests: A Teacher's Manual.

    ERIC Educational Resources Information Center

    Lemieux, Chris; Powers, Jennene; Quinby, Peter; Schultz, Caroline; Stabb, Mark

    "Exploring Old Growth Forests" is an Ontario (Canada) program that provides secondary students with hands-on experiences in old growth forests. Activity-based and student-centered, the program aims to develop student awareness of the importance of old growth forests and the need to conserve them. This manual provides teachers with…

  11. New findings about old-growth forests.

    Treesearch

    Valerie. Rapp

    2003-01-01

    Not all forests with old trees are scientifically defined as old growth. Among those that are, the variations are so striking that multiple definitions of old-growth forests are needed, even when the discussion is restricted to Pacific coast old-growth forests from southwestern Oregon to southwestern British Columbia.Scientists understand the basic structural...

  12. Old growth in northwestern California National Forests. Forest Service research paper

    SciTech Connect

    Beardsley, D.; Warbington, R.

    1996-06-01

    This report estimates old-growth forest area and summarizes stand characteristics of old growth in northwestern California National Forests by forest type. Old-growth definitions for each forest type are used.

  13. Detecting and monitoring acidic deposition effects on soil chemistry and forest growth on the Monongahela National Forest

    Treesearch

    Patricia Elias; James Burger; Stephanie Connolly; Mary Beth. Adams

    2010-01-01

    The Monongahela National Forest (MNF) lies downwind from many sources of acid deposition (AD) pollution. Therefore, managers are concerned about the possible deleterious effects of AD on the forest ecosystem. To address the needs of MNF managers, we used Forest Inventory and Analysis (FIA) sites to evaluate forest growth patterns on the MNF to determine the...

  14. Growth and yield model application in tropical rain forest management

    Treesearch

    James Atta-Boateng; John W., Jr. Moser

    2000-01-01

    Analytical tools are needed to evaluate the impact of management policies on the sustainable use of rain forest. Optimal decisions concerning the level of management inputs require accurate predictions of output at all relevant input levels. Using growth data from 40 l-hectare permanent plots obtained from the semi-deciduous forest of Ghana, a system of 77 differential...

  15. Forest growth in the Douglas fir region.

    Treesearch

    W.H. Meyer; P.A. Briegleb

    1936-01-01

    A study of forest growth in western Oregon and western Washington, the so-called Douglas fir region, was made in 1934-35 by the Pacific Northwest Forest Experiment Station. This is one phase of the Nation-wide forest survey undertaken by the Department of Agriculture under authority of the McSweeney-McNary Forest Research Act. Other phases of the survey are an...

  16. Measurement of Tree Growth in Tropical Forests

    Treesearch

    C. B. Briscoe

    1961-01-01

    The title of my paper--Measurement of Tree Growth in Tropical Forests--is somwhat misleading. Because tree and forest growth determination are essentially the same anywhere, most of what I have to say is as applicable in British Columbia, Japan, or New Zealand as it is in Ecuador or the Philipines.

  17. Development of forest growth inputs from LiDAR

    NASA Astrophysics Data System (ADS)

    Tinkham, W. T.; Falkowski, M. J.; Smith, A. M.; Hudak, A. T.; Crookston, N. L.

    2012-12-01

    Investigating the potential impacts of climate change on forest dynamics is a critical area of science, especially given the vast amount of ecosystems services forests provide. Critical understanding of these impacts is lacking, most visibly, at regional to local scales where on-the-ground management activities are implemented. To plan ahead and mitigate the impacts of climate change, land managers need of decision support tools that can be used to evaluate the future impacts of climate change on forest conditions, so that sustainable management practices that enhance ecosystem resilience can be defensibly developed, evaluated, and implemented. However, to be applicable to both regional forest planning and local operational forest management decisions, approaches must be capable of simulating forest dynamics across large spatial extents (required for regional planning) while maintaining a high-level of spatial detail (required for operational management). Numerous studies have demonstrated that LiDAR remote sensing is an effective tool for accurately measuring forest structure at landscape scales, providing information with a level of detail appropriate for operational forest management. This study attempts to develop a system to spatially parameterize and supply critical initial conditions for Climate-FVS and other forest growth models across major ecoregions (in terms of forest structure and composition) in the Pacific Northwest (PNW) of the US, via an integration of airborne LiDAR, spatial measures of productivity, and local climate. Integrating these inputs into forest growth models would be a big step towards planning and optimizing landscape level alterations to forest structure and productivity from climate change.

  18. Restoring complexity: second-growth forests and habitat diversity.

    Treesearch

    Valerie. Rapp

    2002-01-01

    Old-growth forests supply many important values, including critical habitat for some wildlife species. These forests are most useful for some wildlife species when they exist in large blocks. But many areas dedicated to old-growth values on federal lands are fragmented by patches of second-growth forests planted after timber harvest. These second-growth forests are...

  19. Evidence for environmentally enhanced forest growth

    PubMed Central

    Fang, Jingyun; Kato, Tomomichi; Guo, Zhaodi; Yang, Yuanhe; Hu, Huifeng; Shen, Haihua; Zhao, Xia; Kishimoto-Mo, Ayaka W.; Tang, Yanhong; Houghton, Richard A.

    2014-01-01

    Forests in the middle and high latitudes of the northern hemisphere function as a significant sink for atmospheric carbon dioxide (CO2). This carbon (C) sink has been attributed to two processes: age-related growth after land use change and growth enhancement due to environmental changes, such as elevated CO2, nitrogen deposition, and climate change. However, attribution between these two processes is largely controversial. Here, using a unique time series of an age-class dataset from six national forest inventories in Japan and a new approach developed in this study (i.e., examining changes in biomass density at each age class over the inventory periods), we quantify the growth enhancement due to environmental changes and its contribution to biomass C sink in Japan’s forests. We show that the growth enhancement for four major plantations was 4.0∼7.7 Mg C⋅ha−1 from 1980 to 2005, being 8.4–21.6% of biomass C sequestration per hectare and 4.1–35.5% of the country's total net biomass increase of each forest type. The growth enhancement differs among forest types, age classes, and regions. Our results provide, to our knowledge, the first ground-based evidence that global environmental changes can increase C sequestration in forests on a broad geographic scale and imply that both the traits and age of trees regulate the responses of forest growth to environmental changes. These findings should be incorporated into the prediction of forest C cycling under a changing climate. PMID:24979781

  20. A Forest Tent Caterpillar Outbreak Increased Resource Levels and Seedling Growth in a Northern Hardwood Forest

    PubMed Central

    Rozendaal, Danaë M. A.; Kobe, Richard K.

    2016-01-01

    In closed-canopy forests, gap formation and closure are thought to be major drivers of forest dynamics. Crown defoliation by insects, however, may also influence understory resource levels and thus forest dynamics. We evaluate the effect of a forest tent caterpillar outbreak on understory light availability, soil nutrient levels and tree seedling height growth in six sites with contrasting levels of canopy defoliation in a hardwood forest in northern lower Michigan. We compared resource levels and seedling growth of six hardwood species before, during and in the three years after the outbreak (2008–2012). Canopy openness increased strongly during the forest tent caterpillar outbreak in the four moderately and severely defoliated sites, but not in lightly defoliated sites. Total inorganic soil nitrogen concentrations increased in response to the outbreak in moderately and severely defoliated sites. The increase in total inorganic soil nitrogen was driven by a strong increase in soil nitrate, and tended to become stronger with increasing site defoliation. Seedling height growth increased for all species in the moderately and severely defoliated sites, but not in lightly defoliated sites, either during the outbreak year or in the year after the outbreak. Growth increases did not become stronger with increasing site defoliation, but were strongest in a moderately defoliated site with high soil nutrient levels. Growth increases tended to be strongest for the shade intolerant species Fraxinus americana and Prunus serotina, and the shade tolerant species Ostrya virginiana. The strong growth response of F. americana and P. serotina suggests that recurring forest tent caterpillar outbreaks may facilitate the persistence of shade intolerant species in the understory in the absence of canopy gaps. Overall, our results suggest that recurrent canopy defoliation resulting from cyclical forest insect outbreaks may be an additional driver of dynamics in temperate closed

  1. A Forest Tent Caterpillar Outbreak Increased Resource Levels and Seedling Growth in a Northern Hardwood Forest.

    PubMed

    Rozendaal, Danaë M A; Kobe, Richard K

    2016-01-01

    In closed-canopy forests, gap formation and closure are thought to be major drivers of forest dynamics. Crown defoliation by insects, however, may also influence understory resource levels and thus forest dynamics. We evaluate the effect of a forest tent caterpillar outbreak on understory light availability, soil nutrient levels and tree seedling height growth in six sites with contrasting levels of canopy defoliation in a hardwood forest in northern lower Michigan. We compared resource levels and seedling growth of six hardwood species before, during and in the three years after the outbreak (2008-2012). Canopy openness increased strongly during the forest tent caterpillar outbreak in the four moderately and severely defoliated sites, but not in lightly defoliated sites. Total inorganic soil nitrogen concentrations increased in response to the outbreak in moderately and severely defoliated sites. The increase in total inorganic soil nitrogen was driven by a strong increase in soil nitrate, and tended to become stronger with increasing site defoliation. Seedling height growth increased for all species in the moderately and severely defoliated sites, but not in lightly defoliated sites, either during the outbreak year or in the year after the outbreak. Growth increases did not become stronger with increasing site defoliation, but were strongest in a moderately defoliated site with high soil nutrient levels. Growth increases tended to be strongest for the shade intolerant species Fraxinus americana and Prunus serotina, and the shade tolerant species Ostrya virginiana. The strong growth response of F. americana and P. serotina suggests that recurring forest tent caterpillar outbreaks may facilitate the persistence of shade intolerant species in the understory in the absence of canopy gaps. Overall, our results suggest that recurrent canopy defoliation resulting from cyclical forest insect outbreaks may be an additional driver of dynamics in temperate closed

  2. Adjusting STEMS growth model for Wisconsin forests.

    Treesearch

    Margaret R. Holdaway

    1985-01-01

    Describes a simple procedure for adjusting growth in the STEMS regional tree growth model to compensate for subregional differences. Coefficients are reported to adjust Lake States STEMS to the forests of Northern and Central Wisconsin--an area of essentially uniform climate and similar broad physiographic features. Errors are presented for various combinations of...

  3. The relative contributions of forest growth and areal expansion to forest biomass carbon

    Treesearch

    P. Li; J. Zhu; H. Hu; Z. Guo; Y. Pan; R. Birdsey; J. Fang

    2016-01-01

    Forests play a leading role in regional and global terrestrial carbon (C) cycles. Changes in C sequestration within forests can be attributed to areal expansion (increase in forest area) and forest growth (increase in biomass density). Detailed assessment of the relative contributions of areal expansion and forest growth to C sinks is crucial to reveal the mechanisms...

  4. Evaluating relationships among tree growth rate, shade tolerance, and browse tolerance following disturbance in an eastern deciduous forest

    Treesearch

    Lisa M. Krueger; Chris J. Peterson; Alejandro Royo; Walter P. Carson

    2009-01-01

    Interspecific differences in shade tolerance among woody species are considered a primary driving force underlying forest succession. However, variation in shade tolerance may be only one of many interspecific differences that cause species turnover. For example, tree species may differ in their sensitivity to herbivory. Nonetheless,...

  5. The relative contributions of forest growth and areal expansion to forest biomass carbon

    NASA Astrophysics Data System (ADS)

    Li, P.; Zhu, J.; Hu, H.; Guo, Z.; Pan, Y.; Birdsey, R.; Fang, J.

    2016-01-01

    Forests play a leading role in regional and global terrestrial carbon (C) cycles. Changes in C sequestration within forests can be attributed to areal expansion (increase in forest area) and forest growth (increase in biomass density). Detailed assessment of the relative contributions of areal expansion and forest growth to C sinks is crucial to reveal the mechanisms that control forest C sinks and it is helpful for developing sustainable forest management policies in the face of climate change. Using the Forest Identity concept and forest inventory data, this study quantified the spatial and temporal changes in the relative contributions of forest areal expansion and increased biomass growth to China's forest biomass C sinks from 1977 to 2008. Over the last 30 years, the areal expansion of forests has been a larger contributor to C sinks than forest growth for planted forests in China (62.2 % vs. 37.8 %). However, for natural forests, forest growth has made a larger contribution than areal expansion (60.4 % vs. 39.6 %). For all forests (planted and natural forests), growth in area and density has contributed equally to the total C sinks of forest biomass in China (50.4 % vs. 49.6 %).The relative contribution of forest growth of planted forests showed an increasing trend from an initial 25.3 % to 61.0 % in the later period of 1998 to 2003, but for natural forests, the relative contributions were variable without clear trends, owing to the drastic changes in forest area and biomass density over the last 30 years. Our findings suggest that afforestation will continue to increase the C sink of China's forests in the future, subject to sustainable forest growth after the establishment of plantations.

  6. Ecological characteristics of old-growth Douglas-fir forests.

    Treesearch

    Jerry F. Franklin; Kermit Jr. Cromack; William Denison; Arthur McKee; Chris Maser; James Sedell; Fred Swanson; Glen. Juday

    1981-01-01

    Old-growth coniferous forests differ significantly from young-growth forests in species composition, function (rate and paths of energy flow and nutrient and water cycling), and structure. Most differences can be related to four key structural components of old growth: large live trees, large snags, large logs on land, and large logs in streams. Foresters wishing to...

  7. Old-growth definition for wet pine forests, woodlands, and savannas. Forest Service general technical report

    SciTech Connect

    Harms, W.R.

    1996-09-01

    All Forest Service Stations and Regions began developing old-growth definitions for specific forest types. Definitions will first be developed for broad forest types and based mainly on published information and so must be viewed accordingly. Refinements will be made by the Forest Service as new information becomes available. This document represents 1 of 35 forest types for which old-growth definition will be drafted.

  8. An Old-Growth Definition for Wet Pine Forests, Woodlands, and Savannas

    Treesearch

    William R. Harms

    1996-01-01

    The ecological, site, and vegetation characteristics of pine wetland forests of the flatwoods region of the Southeastern United States are described. Provisional working definitions of old-growth characteristics are provided for longleaf pine, slash pine, and pond pine forests. These definitions can be used to identify and evaluate stands for retention in old-growth...

  9. Environmental control of carbon allocation matters for modelling forest growth.

    PubMed

    Guillemot, Joannès; Francois, Christophe; Hmimina, Gabriel; Dufrêne, Eric; Martin-StPaul, Nicolas K; Soudani, Kamel; Marie, Guillaume; Ourcival, Jean-Marc; Delpierre, Nicolas

    2017-04-01

    We aimed to evaluate the importance of modulations of within-tree carbon (C) allocation by water and low-temperature stress for the prediction of annual forest growth with a process-based model. A new C allocation scheme was implemented in the CASTANEA model that accounts for lagged and direct environmental controls of C allocation. Different approaches (static vs dynamic) to modelling C allocation were then compared in a model-data fusion procedure, using satellite-derived leaf production estimates and biometric measurements at c. 10(4) sites. The modelling of the environmental control of C allocation significantly improved the ability of CASTANEA to predict the spatial and year-to-year variability of aboveground forest growth along regional gradients. A significant effect of the previous year's water stress on the C allocation to leaves and wood was reported. Our results also are consistent with a prominent role of the environmental modulation of sink demand in the wood growth of the studied species. Data available at large scales can inform forest models about the processes driving annual and seasonal C allocation. Our results call for a greater consideration of C allocation drivers, especially sink-demand fluctuations, for the simulations of current and future forest productivity with process-based models.

  10. Managing for old-growth forests: a moving target

    Treesearch

    Thomas A. Spies; Robert J. Pabst

    2013-01-01

    Presentation Abstract Old-growth Douglas-fi r (Pseudotsuga menziesii) forests are a goal for conservation and restoration across millions of acres of federal forest lands in western Oregon and Washington. Where old growth currently exists, management is typically focused on protecting stands and watersheds from logging and high-severity wildfi re. Where old growth was...

  11. Area of old-growth forests in California, Oregon, and Washington. Forest Service research bulletin

    SciTech Connect

    Bolsinger, C.L.; Waddell, K.L.

    1993-12-01

    An area of old-growth forests in California, Oregon, and Washington has declined significantly in the second half of the 20th century. The report summarizes available information on old-growth forest area by ownership in California, Oregon, and Washington. Old-growth definitions used by the various owners and agencies are provided.

  12. An Old-Growth Definition for Southwestern Subtropical Upland Forests

    Treesearch

    David D. Diamond

    1998-01-01

    Mainly evergreen, broad-leaved forests in the Southwestern United States are restricted to the Lower Rio Grande Valley of Texas. The soils and long growing season make this region valuable cropland, and, thus, almost all of the area once occupied by this forest type has been converted to row crops. Remaining old-growth forests are usually dominated by some combination...

  13. Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics.

    PubMed

    Itter, Malcolm S; Finley, Andrew O; D'Amato, Anthony W; Foster, Jane R; Bradford, John B

    2017-06-01

    Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics-changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly

  14. Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics

    USGS Publications Warehouse

    Itter, Malcolm S.; Finley, Andrew O.; D'Amato, Anthony W.; Foster, Jane R.; Bradford, John B.

    2017-01-01

    Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics—changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly

  15. Cutting a young-growth, mixed-conifer stand to California Forest Practice Act Standards

    Treesearch

    Philip M. McDonald

    1973-01-01

    Cutting by the minimum standard of the Rules of California's North Sierra Pine Forest District was evaluated for effects on species composition, seed fall, regeneration, and residual growth at the Challenge Experimental Forest, central California. Cutting removed 74 percent of the stand basal area and 94 percent of the merchantable volume. The heavy cut changed...

  16. Old-growth forests as global carbon sinks.

    PubMed

    Luyssaert, Sebastiaan; Schulze, E-Detlef; Börner, Annett; Knohl, Alexander; Hessenmöller, Dominik; Law, Beverly E; Ciais, Philippe; Grace, John

    2008-09-11

    Old-growth forests remove carbon dioxide from the atmosphere at rates that vary with climate and nitrogen deposition. The sequestered carbon dioxide is stored in live woody tissues and slowly decomposing organic matter in litter and soil. Old-growth forests therefore serve as a global carbon dioxide sink, but they are not protected by international treaties, because it is generally thought that ageing forests cease to accumulate carbon. Here we report a search of literature and databases for forest carbon-flux estimates. We find that in forests between 15 and 800 years of age, net ecosystem productivity (the net carbon balance of the forest including soils) is usually positive. Our results demonstrate that old-growth forests can continue to accumulate carbon, contrary to the long-standing view that they are carbon neutral. Over 30 per cent of the global forest area is unmanaged primary forest, and this area contains the remaining old-growth forests. Half of the primary forests (6 x 10(8) hectares) are located in the boreal and temperate regions of the Northern Hemisphere. On the basis of our analysis, these forests alone sequester about 1.3 +/- 0.5 gigatonnes of carbon per year. Thus, our findings suggest that 15 per cent of the global forest area, which is currently not considered when offsetting increasing atmospheric carbon dioxide concentrations, provides at least 10 per cent of the global net ecosystem productivity. Old-growth forests accumulate carbon for centuries and contain large quantities of it. We expect, however, that much of this carbon, even soil carbon, will move back to the atmosphere if these forests are disturbed.

  17. DRAINMOD-FOREST: Integrated Modeling of Hydrology, Soil Carbon and Nitrogen Dynamics, and Plant Growth for Drained Forests.

    PubMed

    Tian, Shiying; Youssef, Mohamed A; Skaggs, R Wayne; Amatya, Devendra M; Chescheir, G M

    2012-01-01

    We present a hybrid and stand-level forest ecosystem model, DRAINMOD-FOREST, for simulating the hydrology, carbon (C) and nitrogen (N) dynamics, and tree growth for drained forest lands under common silvicultural practices. The model was developed by linking DRAINMOD, the hydrological model, and DRAINMOD-N II, the soil C and N dynamics model, to a forest growth model, which was adapted mainly from the 3-PG model. The forest growth model estimates net primary production, C allocation, and litterfall using physiology-based methods regulated by air temperature, water deficit, stand age, and soil N conditions. The performance of the newly developed DRAINMOD-FOREST model was evaluated using a long-term (21-yr) data set collected from an artificially drained loblolly pine ( L.) plantation in eastern North Carolina, USA. Results indicated that the DRAINMOD-FOREST accurately predicted annual, monthly, and daily drainage, as indicated by Nash-Sutcliffe coefficients of 0.93, 0.87, and 0.75, respectively. The model also predicted annual net primary productivity and dynamics of leaf area index reasonably well. Predicted temporal changes in the organic matter pool on the forest floor and in forest soil were reasonable compared to published literature. Both predicted annual and monthly nitrate export were in good agreement with field measurements, as indicated by Nash-Sutcliffe coefficients above 0.89 and 0.79 for annual and monthly predictions, respectively. This application of DRAINMOD-FOREST demonstrated its capability for predicting hydrology and C and N dynamics in drained forests under limited silvicultural practices. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  18. An Old-Growth Definition for Southern Mixed Hardwood Forests

    Treesearch

    William B. Batista; William J. Platt

    1997-01-01

    This report provides an old-growth definition for the southern mixed hardwood forests based on five exemplary stands that show no evidence of having undergone any natural catastrophe or clearcutting for at least 200 years. This forest type occurs in the U.S. southeastern Coastal Plain from the Carolinas to eastern Texas. The exemplary old-growth stands were restricted...

  19. Comparison of growth response to thinning in oak forests managed as coppice with standards and high forest

    NASA Astrophysics Data System (ADS)

    Gautam, S.; Hasenauer, H.; Pietsch, S. A.

    2009-04-01

    The BIOME-BGC model integrates the main physical, biological and physiological processes based on current understanding of ecophysiology to assess forest ecosystem dynamics. This study evaluates the application of the model to assess the thinning effects on coppiced oak forests in Austria. We analyze the growth response, i.e. growth efficiency (GE), nitrogen use efficiency (NUE), water use efficiency (WUE) and radiation use efficiency (RUE) of oak forests to thinning. The results of coppice with standards and high forests simulations are analysed for differences in simulated growth response after thinning. The forest field data of the year 2006 and the respective model runs are used to evaluate model application. Strong positive relationship (r2 = 0.90) with unbiased results and statistically insignificant differences between predicted and observed volume allows the use of the model as a diagnostic tool to assess management effects. Results indicate that the coppice with standards exhibits a significantly higher yield by 2.97% (i.e. 10 cubic meters per hectare in one rotation), a higher harvest (49.9%) but a lower growing stock (19.69%) than the high forests. The higher growing stock and the lower extraction in the high forests confirm that the high forest sequestrates significantly more carbon than the coppice with standards. Results show that thinning leads to an increase in the GE, the NUE and the WUE, and to a decrease in the RUE. Although the coppice with standards forest ecosystem exhibits higher values in all studied growth parameters, only the difference in the NUE was statistically significant. This verifies that the difference in the yield between the coppice with standards and the high forests is mainly governed by the NUE difference in stands after thinning. The coppice with standards system produces an equal amount of net primary production while consuming significantly less nitrogen (16%) compared to the high forest system. In the coppice with

  20. Late-successional and old-growth forest effectiveness monitoring plan for the Northwest Forest Plan.

    Treesearch

    Miles Hemstrom; Thomas Spies; Craig Palmer; Ross Kiester; John Teply; Phil McDonald; Ralph. Warbington

    1998-01-01

    This report presents options for long-term effectiveness monitoring of late-successional and old-growth forests under the Northwest Forest Plan. It describes methods to answer questions about how much late-successional forest exists on Federal land, its pattern, how it’s changing, and if the Forest Plan is providing for its conservation and management. It specifies...

  1. Updating Indiana Annual Forest Inventory and Analysis Plot Data Using Eastern Broadleaf Forest Diameter Growth Models

    Treesearch

    Veronica C. Lessard

    2001-01-01

    The Forest Inventory and Analysis (FIA) program of the North Central Research Station (NCRS), USDA Forest Service, has developed nonlinear, individual-tree, distance-independent annual diameter growth models. The models are calibrated for species groups and formulated as the product of an average diameter growth component and a modifier component. The regional models...

  2. Forest growth of Mississippi's north unit - A case study of the Southern Forest surveys growth estimation procedures

    Treesearch

    Dennis M. May

    1988-01-01

    This report presents the procedures by which the Southern Forest Inventory and Analysis unit estimates forest growth from permanent horizontal point samples. Inventory data from the 1977-87 survey of Mississippi's north unit were used to demonstrate how trees on the horizontal point samples are classified into one of eight components of growth and, in turn, how...

  3. Comparison of an empirical forest growth and yield simulator and a forest gap simulator using actual 30-year growth from two even-aged forests in Kentucky

    Treesearch

    Daniel A. Yaussy

    2000-01-01

    Two individual-tree growth simulators are used to predict the growth and mortality on a 30-year-old forest site and an 80-year-old forest site in eastern Kentucky. The empirical growth and yield model (NE-TWIGS) was developed to simulate short-term (

  4. Forest structure, stand composition, and climate-growth response in montane forests of Jiuzhaigou National Nature Reserve, China.

    PubMed

    Schwartz, Mark W; Dolanc, Christopher R; Gao, Hui; Strauss, Sharon Y; Schwartz, Ari C; Williams, John N; Tang, Ya

    2013-01-01

    Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1) whether the forest appears in transition toward increased hardwood composition; 2) if conifers appear stressed by recent climate change relative to hardwoods; and 3) how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20(th) century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix) strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth.

  5. Forest Structure, Stand Composition, and Climate-Growth Response in Montane Forests of Jiuzhaigou National Nature Reserve, China

    PubMed Central

    Schwartz, Mark W.; Dolanc, Christopher R.; Gao, Hui; Strauss, Sharon Y.; Schwartz, Ari C.; Williams, John N.; Tang, Ya

    2013-01-01

    Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1) whether the forest appears in transition toward increased hardwood composition; 2) if conifers appear stressed by recent climate change relative to hardwoods; and 3) how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20th century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix) strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth. PMID:23951188

  6. Status of growth and yield information for northern forest types

    Treesearch

    Dale S. Solomon

    1977-01-01

    Existing regional growth-and-yield information for most of the northern forest types is summarized by species. Present research is concentrated on growth-simulation models, constructed by either aggregating available information or through individual tree growth studies. A uniformity of more refined measurements is needed so that future growth models can be tried for...

  7. Forest management is associated with physiological stress in an old-growth forest passerine.

    PubMed Central

    Suorsa, Petri; Huhta, Esa; Nikula, Ari; Nikinmaa, Mikko; Jäntti, Ari; Helle, Heikki; Hakkarainen, Harri

    2003-01-01

    We investigated how physiological stress in an area-sensitive old-growth forest passerine, the Eurasian treecreeper (Certhia familiaris), is associated with forest fragmentation and forest structure. We found evidence that the concentrations of plasma corticosterone in chicks were higher under poor food supply in dense, young forests than in sparse, old forests. In addition, nestlings in large forest patches had lower corticosterone levels and a better body condition than in small forest patches. In general, corticosterone levels were negatively related to body condition and survival. We also found a decrease in corticosterone levels within the breeding season, which may have been a result of an increase in food supply from the first to the second broods. Our results suggest that forest fragmentation may decrease the fitness of free-living individual treecreepers. PMID:12803912

  8. Winter climate limits subantarctic low forest growth and establishment.

    PubMed

    Harsch, Melanie A; McGlone, Matt S; Wilmshurst, Janet M

    2014-01-01

    Campbell Island, an isolated island 600 km south of New Zealand mainland (52 °S, 169 °E) is oceanic (Conrad Index of Continentality  =  -5) with small differences between mean summer and winter temperatures. Previous work established the unexpected result that a mean annual climate warming of c. 0.6 °C since the 1940's has not led to upward movement of the forest limit. Here we explore the relative importance of summer and winter climatic conditions on growth and age-class structure of the treeline forming species, Dracophyllum longifolium and Dracophyllum scoparium over the second half of the 20th century. The relationship between climate and growth and establishment were evaluated using standard dendroecological methods and local climate data from a meteorological station on the island. Growth and establishment were correlated against climate variables and further evaluated within hierarchical regression models to take into account the effect of plot level variables. Winter climatic conditions exerted a greater effect on growth and establishment than summer climatic conditions. Establishment is maximized under warm (mean winter temperatures >7 °C), dry winters (total winter precipitation <400 mm). Growth, on the other hand, is adversely affected by wide winter temperature ranges and increased rainfall. The contrasting effect of winter warmth on growth and establishment suggests that winter temperature affects growth and establishment through differing mechanisms. We propose that milder winters enhance survival of seedlings and, therefore, recruitment, but increases metabolic stress on established plants, resulting in lower growth rates. Future winter warming may therefore have complex effects on plant growth and establishment globally.

  9. Winter Climate Limits Subantarctic Low Forest Growth and Establishment

    PubMed Central

    Harsch, Melanie A.; McGlone, Matt S.; Wilmshurst, Janet M.

    2014-01-01

    Campbell Island, an isolated island 600 km south of New Zealand mainland (52°S, 169°E) is oceanic (Conrad Index of Continentality  = −5) with small differences between mean summer and winter temperatures. Previous work established the unexpected result that a mean annual climate warming of c. 0.6°C since the 1940's has not led to upward movement of the forest limit. Here we explore the relative importance of summer and winter climatic conditions on growth and age-class structure of the treeline forming species, Dracophyllum longifolium and Dracophyllum scoparium over the second half of the 20th century. The relationship between climate and growth and establishment were evaluated using standard dendroecological methods and local climate data from a meteorological station on the island. Growth and establishment were correlated against climate variables and further evaluated within hierarchical regression models to take into account the effect of plot level variables. Winter climatic conditions exerted a greater effect on growth and establishment than summer climatic conditions. Establishment is maximized under warm (mean winter temperatures >7 °C), dry winters (total winter precipitation <400 mm). Growth, on the other hand, is adversely affected by wide winter temperature ranges and increased rainfall. The contrasting effect of winter warmth on growth and establishment suggests that winter temperature affects growth and establishment through differing mechanisms. We propose that milder winters enhance survival of seedlings and, therefore, recruitment, but increases metabolic stress on established plants, resulting in lower growth rates. Future winter warming may therefore have complex effects on plant growth and establishment globally. PMID:24691026

  10. Structure and development of old-growth, unmanaged second-growth, and extended rotation Pinus resinosa forests in Minnesota, USA

    USGS Publications Warehouse

    Silver, Emily J.; D'Amato, Anthony W.; Fraver, Shawn; Palik, Brian J.; Bradford, John B.

    2013-01-01

    The structure and developmental dynamics of old-growth forests often serve as important baselines for restoration prescriptions aimed at promoting more complex structural conditions in managed forest landscapes. Nonetheless, long-term information on natural patterns of development is rare for many commercially important and ecologically widespread forest types. Moreover, the effectiveness of approaches recommended for restoring old-growth structural conditions to managed forests, such as the application of extended rotation forestry, has been little studied. This study uses several long-term datasets from old growth, extended rotation, and unmanaged second growth Pinus resinosa (red pine) forests in northern Minnesota, USA, to quantify the range of variation in structural conditions for this forest type and to evaluate the effectiveness of extended rotation forestry at promoting the development of late-successional structural conditions. Long-term tree population data from permanent plots for one of the old-growth stands and the extended rotation stands (87 and 61 years, respectively) also allowed for an examination of the long-term structural dynamics of these systems. Old-growth forests were more structurally complex than unmanaged second-growth and extended rotation red pine stands, due in large part to the significantly higher volumes of coarse woody debris (70.7 vs. 11.5 and 4.7 m3/ha, respectively) and higher snag basal area (6.9 vs. 2.9 and 0.5 m2/ha, respectively). In addition, old-growth forests, although red pine-dominated, contained a greater abundance of other species, including Pinus strobus, Abies balsamea, and Picea glauca relative to the other stand types examined. These differences between stand types largely reflect historic gap-scale disturbances within the old-growth systems and their corresponding structural and compositional legacies. Nonetheless, extended rotation thinning treatments, by accelerating advancement to larger tree diameter

  11. DRAINMOD-FOREST: Integrated modeling of hydrology, soil carbon and nitrogen dynamics, and plant growth for drained forests

    Treesearch

    Shiying Tian; Mohamed A. Youssef; R. Wayne Skaggs; Devendra M. Amatya; G.M. Chescheir

    2012-01-01

    We present a hybrid and stand-level forest ecosystem model, DRAINMOD-FOREST, for simulating the hydrology, carbon (C) and nitrogen (N) dynamics, and tree growth for drained forest lands under common silvicultural practices. The model was developed by linking DRAINMOD, the hydrological model, and DRAINMOD-N II, the soil C and N dynamics model, to a forest growth model,...

  12. Sciurids in Pacific Northwest managed and old-growth forests.

    Treesearch

    A.B. Carey

    1995-01-01

    An understanding of the factors governing sciurid abundance in the Pacific Northwest is essential for prescribing forest management practices for second-growth forests where recovery of Spotted Owl (Strix occidentalis) populations and enhancement of biodiversity are objectives. We compared results of companion studies of sciurids in western...

  13. Analyzing growth and mortality in a subtropical urban forest ecosystem

    Treesearch

    Alicia B. Lawrence; Fancisco J. Escobedo; Christina L. Staudhammera; Wayne Zipperer Zipperer

    2012-01-01

    Information on urban tree growth, mortality and in-growth is currently being used to estimate urban forest structure changes and ecosystem services such as carbon sequestration. This study reports on tree diameter growth and mortality in 65 plots distributed among four land use categories, which were established in 2005/2006 in Gainesville, Florida, USA and were re-...

  14. Observed forest sensitivity to climate implies large changes in 21st century North American forest growth.

    PubMed

    Charney, Noah D; Babst, Flurin; Poulter, Benjamin; Record, Sydne; Trouet, Valerie M; Frank, David; Enquist, Brian J; Evans, Margaret E K

    2016-09-01

    Predicting long-term trends in forest growth requires accurate characterisation of how the relationship between forest productivity and climatic stress varies across climatic regimes. Using a network of over two million tree-ring observations spanning North America and a space-for-time substitution methodology, we forecast climate impacts on future forest growth. We explored differing scenarios of increased water-use efficiency (WUE) due to CO2 -fertilisation, which we simulated as increased effective precipitation. In our forecasts: (1) climate change negatively impacted forest growth rates in the interior west and positively impacted forest growth along the western, southeastern and northeastern coasts; (2) shifting climate sensitivities offset positive effects of warming on high-latitude forests, leaving no evidence for continued 'boreal greening'; and (3) it took a 72% WUE enhancement to compensate for continentally averaged growth declines under RCP 8.5. Our results highlight the importance of locally adapted forest management strategies to handle regional differences in growth responses to climate change. © 2016 John Wiley & Sons Ltd/CNRS.

  15. Responses in the growth of the northern forest biomes to a CO{sub 2}-induced climatic change, as evaluated by the Frankfurt Biosphere Model (FBM)

    SciTech Connect

    Hager, C.; Wurth, G.; Wagner, U.; Kohlmaier, G.H.

    1996-12-31

    The Frankfurt Biosphere Model (FBM), a mechanistic, seasonal and prognostic compartment model of the terrestrial biosphere, has been developed in recent years to simulate the carbon exchange fluxes between the vegetation and the atmosphere with a spatial resolution of 0.5{degree} x 0.5{degree} on a global scale. In this contribution the authors use the FBM to assess the possible changes in the transient response of the northern forest biomes under a future 2 {times} CO{sub 2} climate. The development of these ecosystems from its initial seedling state to its climax state is simulated under different climatic conditions. In their simulations the 2 {times} CO{sub 2} climate provided by the GCM of the MPI fuer Meteorologie in Hamburg (ECHAM) is used. The differences in vegetation`s growth under contemporary and future climate can be assessed by performing two model runs with the same parameterization but with different driving climatic variables for each vegetation type and location.

  16. Relictual amphibians and old-growth forest

    Treesearch

    H.H. Welsh

    1990-01-01

    Terrestrial and aquatic herpetofauna were sampled by pitfall traps, time-constrained searches, and areaconstrained searches (stream sites only) over a three-year period to examine the importance of forest age to amphibians and reptiles. Fifty-four terrestrial and 39 aquatic sites in Douglas-fir-dominated, mixed evergreen forests were located in southwestern Oregon and...

  17. Old-growth forests can accumulate carbon in soils

    USGS Publications Warehouse

    Zhou, G.; Liu, S.; Li, Z.; Zhang, Dongxiao; Tang, X.; Zhou, C.; Yan, J.; Mo, J.

    2006-01-01

    Old-growth forests have traditionally been considered negligible as carbon sinks because carbon uptake has been thought to be balanced by respiration. We show that the top 20-centimeter soil layer in preserved old-growth forests in southern China accumulated atmospheric carbon at an unexpectedly high average rate of 0.61 megagrams of carbon hectare-1 year-1 from 1979 to 2003. This study suggests that the carbon cycle processes in the belowground system of these forests are changing in response to the changing environment. The result directly challenges the prevailing belief in ecosystem ecology regarding carbon budget in old-growth forests and supports the establishment of a new, nonequilibrium conceptual framework to study soil carbon dynamics.

  18. Carbon changes in conterminous US forests associated with growth and major disturbances: 1992-2001

    Treesearch

    Daolan Zheng; Linda S. Heath; Mark J. Ducey; James E. Smith

    2011-01-01

    We estimated forest area and carbon changes in the conterminous United States using a remote sensing based land cover change map, forest fire data from the Monitoring Trends in Burn Severity program, and forest growth and harvest data from the USDA Forest Service, Forest Inventory and Analysis Program. Natural and human-associated disturbances reduced the forest...

  19. Light, nutrients and the growth of herbaceous forest species

    NASA Astrophysics Data System (ADS)

    Elemans, Marjet

    2004-12-01

    The herb layer of forests planted on former agricultural land often differs from that of old-growth forest. This study investigates if the expected increased nutrient availability in the shaded conditions of newly planted forests and the plasticity of the species to adjust their biomass allocation to different levels of light and nutrients help to explain these differences in the herb layers of the two forest types. In a greenhouse experiment biomass distribution and production of two species characteristic for the highly shaded forest floor, Circaea lutetiana and Mercurialis perennis, and two species more common in the forest-edge, Aegopodium podagraria and Impatiens parviflora were studied at different levels of light (2%, 8% and 66% of the full light level) and nutrients (30 and 300 kg N ha -1 per year). The main factor affecting allocation and biomass production was light availability. Nutrient supply only had a significant effect at the higher light levels. Species were mainly plastic to changes in light and the two species from the forest floor showed to be more rigid in allocation pattern than the species from the forest-edge. So, although the species from the forest-edge were more plastic, they did not profit from the increased nutrient supply because the main factor affecting biomass distribution and production was light availability.

  20. Information system of forest growth and productivity by site quality type and elements of forest

    NASA Astrophysics Data System (ADS)

    Khlyustov, V.

    2012-04-01

    Information system of forest growth and productivity by site quality type and elements of forest V.K. Khlustov Head of the Forestry Department of Russian State Agrarian University named after K.A.Timiryazev doctor of agricultural sciences, professor The efficiency of forest management can be improved substantially by development and introduction of principally new models of forest growth and productivity dynamics based on regionalized site specific parameters. Therefore an innovative information system was developed. It describes the current state and gives a forecast for forest stand parameters: growth, structure, commercial and biological productivity depend on type of site quality. In contrast to existing yield tables, the new system has environmental basis: site quality type. The information system contains set of multivariate statistical models and can work at the level of individual trees or at the stand level. The system provides a graphical visualization, as well as export of the emulation results. The System is able to calculate detailed description of any forest stand based on five initial indicators: site quality type, site index, stocking, composition, and tree age by elements of the forest. The results of the model run are following parameters: average diameter and height, top height, number of trees, basal area, growing stock (total, commercial with distribution by size, firewood and residuals), live biomass (stem, bark, branches, foliage). The system also provides the distribution of mentioned above forest stand parameters by tree diameter classes. To predict the future forest stand dynamics the system require in addition the time slot only. Full set of forest parameters mention above will be provided by the System. The most conservative initial parameters (site quality type and site index) can be kept in the form of geo referenced polygons. In this case the system would need only 3 dynamic initial parameters (stocking, composition and age) to

  1. Ecological setting of the Wind River old-growth forest.

    Treesearch

    David C. Shaw; Jerry F. Franklin; Ken Bible; Jeffrey Klopatek; Elizabeth Freeman; Sarah Greene; Geoffrey G. Parker

    2004-01-01

    The Wind River old-growth forest, in the southern Cascade Range of Washington State, is a cool (average annual temperature, 8.7°C), moist (average annual precipitation, 2223 mm), 500-year-old Douglas-fir-western hemlock forest of moderate to low productivity at 371-m elevation on a less than 10% slope. There is a seasonal snowpack (November-March), and rain-on-snow and...

  2. Comparative physiology of a central hardwood old-growth forest canopy and forest gap

    Treesearch

    A. R. Gillespie; J. Waterman; K. Saylors

    1993-01-01

    Concerns of poor oak regeneration, changing climate, biodiversity patterns, and carbon cycling in the Central Hardwoods have prompted ecological and physiological studies of old-growth forests and their role in maintaining the landscape. To examine the effects of old-growth canopy structure on the physiological productivity of overstory and understory species, we...

  3. Comparing models for growth and management of forest tracts

    Treesearch

    J.J. Colbert; Michael Schuckers; Desta Fekedulegn

    2003-01-01

    The Stand Damage Model (SDM) is a PC-based model that is easily installed, calibrated and initialized for use in exploring the future growth and management of forest stands or small wood lots. We compare the basic individual tree growth model incorporated in this model with alternative models that predict the basal area growth of trees. The SDM is a gap-type simulator...

  4. A dynamic model for intertemporal allocation of old-growth forests in the Pacific Northwest.

    PubMed

    Carver, Andrew D; Lee, John G; LeMaster, Dennis C

    2002-12-01

    Across the globe, continued policy debates regarding the management of old-growth forests center around the difficult task of balancing economic and ecological considerations. Though the forests of the Pacific Northwest United States are among the most studied old-growth ecosystems, ecological and economic analyses have yielded public land management directives that remain controversial. Specifically, the recently adopted Northwest Forest Plan lacks explicit goals for maintaining intergenerational equity for the use of forest resources and the diversity of old-growth ecosystems. Unlike previous studies which rely on monetary quantification of costs and benefits, this study develops and applies a conceptual framework for evaluating socially optimal Pacific Northwest old-growth forest utilization strategies. Conditions for the optimal management of old-growth forests are derived using dynamic programming. The objective function synthesizes relevant biological and economic attributes of the old-growth allocation problem. Results in the form of extraction paths are compared given social pressure for consumptive and non-consumptive benefits, as well as different planning horizons, rates of social time preference, and environmental variance. Lengthening the planning horizon results in a vast divergence of optimal policies in the absence of discounting. Extraction rates appear to approach zero as the planning horizon approaches infinity. While higher rates of social time preference increase the rate of extraction, forest stocks remaining at the terminal time period equal levels remaining with a lower discount rate. Increasing environmental variance results in a higher level of stock remaining at the terminal time period. This analysis, while specific to the old-growth controversy of the Pacific Northwest, does provide general guidelines for addressing similar problems of multiple uses of natural areas, particularly where such uses are mutually incompatible, or where one

  5. Evidence for a recent increase in forest growth

    PubMed Central

    McMahon, Sean M.; Parker, Geoffrey G.; Miller, Dawn R.

    2010-01-01

    Forests and their soils contain the majority of the earth’s terrestrial carbon stocks. Changes in patterns of tree growth can have a huge impact on atmospheric cycles, biogeochemical cycles, climate change, and biodiversity. Recent studies have shown increases in biomass across many forest types. This increase has been attributed to climate change. However, without knowing the disturbance history of a forest, growth could also be caused by normal recovery from unknown disturbances. Using a unique dataset of tree biomass collected over the past 22 years from 55 temperate forest plots with known land-use histories and stand ages ranging from 5 to 250 years, we found that recent biomass accumulation greatly exceeded the expected growth caused by natural recovery. We have also collected over 100 years of local weather measurements and 17 years of on-site atmospheric CO2 measurements that show consistent increases in line with globally observed climate-change patterns. Combined, these observations show that changes in temperature and CO2 that have been observed worldwide can fundamentally alter the rate of critical natural processes, which is predicted by biogeochemical models. Identifying this rate change is important to research on the current state of carbon stocks and the fluxes that influence how carbon moves between storage and the atmosphere. These results signal a pressing need to better understand the changes in growth rates in forest systems, which influence current and future states of the atmosphere and biosphere. PMID:20133710

  6. Forests fuel fish growth in freshwater deltas

    PubMed Central

    Tanentzap, Andrew J.; Szkokan-Emilson, Erik J.; Kielstra, Brian W.; Arts, Michael T.; Yan, Norman D.; Gunn, John M.

    2014-01-01

    Aquatic ecosystems are fuelled by biogeochemical inputs from surrounding lands and within-lake primary production. Disturbances that change these inputs may affect how aquatic ecosystems function and deliver services vital to humans. Here we test, using a forest cover gradient across eight separate catchments, whether disturbances that remove terrestrial biomass lower organic matter inputs into freshwater lakes, thereby reducing food web productivity. We focus on deltas formed at the stream-lake interface where terrestrial-derived particulate material is deposited. We find that organic matter export increases from more forested catchments, enhancing bacterial biomass. This transfers energy upwards through communities of heavier zooplankton, leading to a fourfold increase in weights of planktivorous young-of-the-year fish. At least 34% of fish biomass is supported by terrestrial primary production, increasing to 66% with greater forest cover. Habitat tracers confirm fish were closely associated with individual catchments, demonstrating that watershed protection and restoration increase biomass in critical life-stages of fish. PMID:24915965

  7. Forest biomass carbon sinks in East Asia, with special reference to the relative contributions of forest expansion and forest growth.

    PubMed

    Fang, Jingyun; Guo, Zhaodi; Hu, Huifeng; Kato, Tomomichi; Muraoka, Hiroyuki; Son, Yowhan

    2014-06-01

    Forests play an important role in regional and global carbon (C) cycles. With extensive afforestation and reforestation efforts over the last several decades, forests in East Asia have largely expanded, but the dynamics of their C stocks have not been fully assessed. We estimated biomass C stocks of the forests in all five East Asian countries (China, Japan, North Korea, South Korea, and Mongolia) between the 1970s and the 2000s, using the biomass expansion factor method and forest inventory data. Forest area and biomass C density in the whole region increased from 179.78 × 10(6) ha and 38.6 Mg C ha(-1) in the 1970s to 196.65 × 10(6) ha and 45.5 Mg C ha(-1) in the 2000s, respectively. The C stock increased from 6.9 Pg C to 8.9 Pg C, with an averaged sequestration rate of 66.9 Tg C yr(-1). Among the five countries, China and Japan were two major contributors to the total region's forest C sink, with respective contributions of 71.1% and 32.9%. In China, the areal expansion of forest land was a larger contributor to C sinks than increased biomass density for all forests (60.0% vs. 40.0%) and for planted forests (58.1% vs. 41.9%), while the latter contributed more than the former for natural forests (87.0% vs. 13.0%). In Japan, increased biomass density dominated the C sink for all (101.5%), planted (91.1%), and natural (123.8%) forests. Forests in South Korea also acted as a C sink, contributing 9.4% of the total region's sink because of increased forest growth (98.6%). Compared to these countries, the reduction in forest land in both North Korea and Mongolia caused a C loss at an average rate of 9.0 Tg C yr(-1), equal to 13.4% of the total region's C sink. Over the last four decades, the biomass C sequestration by East Asia's forests offset 5.8% of its contemporary fossil-fuel CO2 emissions. © 2014 John Wiley & Sons Ltd.

  8. Carbon Uptake and Storage in Old-Growth and Second-Growth Forests in Central Vermont

    NASA Astrophysics Data System (ADS)

    Lloyd, A. H.; Weisser, O.

    2013-12-01

    Managing forests towards the goal of maximizing carbon uptake and storage provides an important tool for climate change mitigation. There is significant spatial and temporal variation among forests, even within an ecosystem type, in annual uptake and storage of carbon. Understanding the causes for that variation is important in refining management practices and restoration goals that promote carbon storage. We explore the variation in carbon storage and uptake among forests differing in age in central Vermont, comparing young, intermediate-aged, and old-growth forests. We generally expected that younger forests would have a higher annual uptake of carbon than older forests. Significant uncertainty exists, however, about the temporal trajectory from a young, rapidly growing forest to an old-growth forest that may be in a steady-state, with no net uptake of carbon. Within each forest, we compare differences among functional groups of species (e.g., hardwoods versus softwoods) in contribution to overall forest carbon uptake and storage. Our study sites include an old-growth hemlock/mixed hardwood forest that has not been directly affected by human activities, and which contains trees upwards of 350 years old; a 130-year-old mixed hardwood forest that has recolonized former pasture land; and a 90-year-old mixed hardwood forest on formerly agricultural floodplain land. Carbon storage in live and dead biomass pools was estimated from allometric equations, based on repeated measurements of tree diameters in permanently marked study plots. Historical patterns of carbon storage in living biomass were estimated by reconstructing tree diameter from measured increment cores, and then estimating the living biomass in each year. As expected, the old-growth forest stored almost twice the C in live biomass as the two second-growth forests, which stored equivalent amounts of carbon, despite the difference in age. Dead biomass was a larger pool of C in the old-growth forest than in

  9. A dynamic ecosystem growth model for forests at high complexity structure

    NASA Astrophysics Data System (ADS)

    Collalti, A.; Perugini, L.; Chiti, T.; Matteucci, G.; Oriani, A.; Santini, M.; Papale, D.; Valentini, R.

    2012-04-01

    Forests ecosystem play an important role in carbon cycle, biodiversity conservation and for other ecosystem services and changes in their structure and status perturb a delicate equilibrium that involves not only vegetation components but also biogeochemical cycles and global climate. The approaches to determine the magnitude of these effects are nowadays various and one of those include the use of models able to simulate structural changes and the variations in forests yield The present work shows the development of a forest dynamic model, on ecosystem spatial scale using the well known light use efficiency to determine Gross Primary Production. The model is predictive and permits to simulate processes that determine forest growth, its dynamic and the effects of forest management using eco-physiological parameters easy to be assessed and to be measured. The model has been designed to consider a tri-dimensional cell structure composed by different vertical layers depending on the forest type that has to be simulated. These features enable the model to work on multi-layer and multi-species forest types, typical of Mediterranean environment, at the resolution of one hectare and at monthly time-step. The model simulates, for each layer, a value of available Photosynthetic Active Radiation (PAR) through Leaf Area Index, Light Extinction Coefficient and cell coverage, the transpiration rate that is closely linked to the intercepted light and the evaporation from soil. Using this model it is possible to evaluate the possible impacts of climate change on forests that may result in decrease or increase of productivity as well as the feedback of one or more dominated layers in terms of CO2 uptake in a forest stand and the effects of forest management activities during the forest harvesting cycle. The model has been parameterised, validated and applied in a multi-layer, multi-age and multi-species Italian turkey oak forest (Q. cerris L., C. betulus L. and C. avellana L

  10. Test of four stand growth simulators for the northeastern United States. Forest Service research paper

    SciTech Connect

    Schuler, T.M.; Marquis, D.A.; Ernst, R.L.; Simpson, B.T.

    1993-09-01

    SILVAH, FIBER, NE-TWIGS, and OAKSIM simulators, commonly used in the northeastern United States, were evaluated by comparing predicted stand development with actual stand development records for periods ranging from 15 to 50 years. Results varied with stand parameter, forest type, projection length, and geographic area. Except in the spruce-fir forest type where FIBER stands out as the best simulator, no single simulator is clearly superior to the others for all locations within a forest type. In general, FIBER, NE-TWIGS, and SILVAH performed best in the northern hardwood (beech-birch-maple) forest type: NE-TWIGS and SILVAH performed best in the Allegheny hardwood (cherry-maple) forest type; SILVAH and OAKSIM performed best in the oak-hickory forest type; and SILVAH was most suitable in the transition hardwood (mixture of northern hardwoods and oaks) forest type. The results give growth and yield model users more information for selecting the simulator most suitable for their particular needs. The results also can be used as a diagnostic tool for growth and yield model development.

  11. Spatial and Temporal Relationships of Old-Growth and Secondary Forests in Indiana, USA

    Treesearch

    Martin A. Spetich; George R. Parker; Eric J. Gustafson

    1997-01-01

    We examined the spatial pattern of forests in Indiana to: (1) determine the extent, connectivity and percent edge of all forests, (2) examine the change in connectivity among these forests if all riparian zones were replanted to forest or other native vegetation, (3) determine the location, spatial dispersion and percent edge of current old-growth forest remnants, (4)...

  12. Structure and dynamics of an upland old-growth forest at Redwood National Park, California

    Treesearch

    Phillip J. van Mantgem; John D. Stuart

    2012-01-01

    Many current redwood forest management targets are based on old-growth conditions, so it is critical that we understand the variability and range of conditions that constitute these forests. Here we present information on the structure and dynamics from six one-hectare forest monitoring plots in an upland old-growth forest at Redwood National Park, California. We...

  13. Characterization of an Old-Growth Forest in the Cross Timbers of Oklahoma

    Treesearch

    S.L. Clark; S.W. Hallgren

    2004-01-01

    Many cross timbers forests in central Oklahoma were neither extensively logged nor farmed and may contain some of the largest tracts of old-growth forests, particularly those dominated by oak, in eastern North America (Therrell and Stahle 1998). We studied a 90 ha old-growth forest in Osage County, Oklahoma which is one of the few designated forest preserves in the...

  14. Biodiversity Promotes Tree Growth during Succession in Subtropical Forest

    PubMed Central

    Barrufol, Martin; Schmid, Bernhard; Bruelheide, Helge; Chi, Xiulian; Hector, Andrew; Ma, Keping; Michalski, Stefan; Tang, Zhiyao; Niklaus, Pascal A.

    2013-01-01

    Losses of plant species diversity can affect ecosystem functioning, with decreased primary productivity being the most frequently reported effect in experimental plant assemblages, including tree plantations. Less is known about the role of biodiversity in natural ecosystems, including forests, despite their importance for global biogeochemical cycling and climate. In general, experimental manipulations of tree diversity will take decades to yield final results. To date, biodiversity effects in natural forests therefore have only been reported from sample surveys or meta-analyses with plots not initially selected for diversity. We studied biomass and growth of subtropical forests stands in southeastern China. Taking advantage of variation in species recruitment during secondary succession, we adopted a comparative study design selecting forest plots to span a gradient in species richness. We repeatedly censored the stem diameter of two tree size cohorts, comprising 93 species belonging to 57 genera and 33 families. Tree size and growth were analyzed in dependence of species richness, the functional diversity of growth-related traits, and phylogenetic diversity, using both general linear and structural equation modeling. Successional age covaried with diversity, but differently so in the two size cohorts. Plot-level stem basal area and growth were positively related with species richness, while growth was negatively related to successional age. The productivity increase in species-rich, functionally and phylogenetically diverse plots was driven by both larger mean sizes and larger numbers of trees. The biodiversity effects we report exceed those from experimental studies, sample surveys and meta-analyses, suggesting that subtropical tree diversity is an important driver of forest productivity and re-growth after disturbance that supports the provision of ecological services by these ecosystems. PMID:24303037

  15. Biodiversity promotes tree growth during succession in subtropical forest.

    PubMed

    Barrufol, Martin; Schmid, Bernhard; Bruelheide, Helge; Chi, Xiulian; Hector, Andrew; Ma, Keping; Michalski, Stefan; Tang, Zhiyao; Niklaus, Pascal A

    2013-01-01

    Losses of plant species diversity can affect ecosystem functioning, with decreased primary productivity being the most frequently reported effect in experimental plant assemblages, including tree plantations. Less is known about the role of biodiversity in natural ecosystems, including forests, despite their importance for global biogeochemical cycling and climate. In general, experimental manipulations of tree diversity will take decades to yield final results. To date, biodiversity effects in natural forests therefore have only been reported from sample surveys or meta-analyses with plots not initially selected for diversity. We studied biomass and growth of subtropical forests stands in southeastern China. Taking advantage of variation in species recruitment during secondary succession, we adopted a comparative study design selecting forest plots to span a gradient in species richness. We repeatedly censored the stem diameter of two tree size cohorts, comprising 93 species belonging to 57 genera and 33 families. Tree size and growth were analyzed in dependence of species richness, the functional diversity of growth-related traits, and phylogenetic diversity, using both general linear and structural equation modeling. Successional age covaried with diversity, but differently so in the two size cohorts. Plot-level stem basal area and growth were positively related with species richness, while growth was negatively related to successional age. The productivity increase in species-rich, functionally and phylogenetically diverse plots was driven by both larger mean sizes and larger numbers of trees. The biodiversity effects we report exceed those from experimental studies, sample surveys and meta-analyses, suggesting that subtropical tree diversity is an important driver of forest productivity and re-growth after disturbance that supports the provision of ecological services by these ecosystems.

  16. Assessment of climate change impacts on forest growth via ecohydrological distributed modelling

    NASA Astrophysics Data System (ADS)

    Rulli, M.; Rossini, V.; Rosso, R.

    2010-12-01

    Climate output from the Hadley Centre's HadCM2 and HadCM3 experiments for the period 1950 to 2100, with IS92a greenhouse gas forcing, together with predicted patterns of increasing CO2, were input to the dynamic spatially distributed ecohydrological model Augusto (Rulli and Rosso, 2005; Rulli 2010). The model integrates the effects of vegetation on the hydrological budget and concurrently the effects of hydrological fluxes on the dynamics of forest growth. The basic structure of the distributed hydrological model analyzes the energy and water fluxes over a complex topography river basin by considering contour based description and tube fluxes basin portioning method. Forest growth is evaluated by considering radiation use efficiency, carbon balance and allocation. Feedbacks between vegetation and hydrological fluxes as well water and light competition are accounted step by step. The ecohydrological model was applied to the WS3 HJ Andrews Experimental Forest where forest growth dynamic was evaluated by estimating two indicators, MAI (Mean Annual Increment) and PAI (Periodic Annual Increment). Model performances were evaluated by comparing observed data (20 years) vs simulation for any single flux founding good agreement. In addition, model capability was confirmed by comparing both PAI and MAI simulated values of forest productivity with those obtained from field surveys. Model simulations were then carried out to evaluate the constraints imposed by climatic change scenario that involves modifications in temperatures, precipitation, vapour pressure deficit, wind speed and radiation as well as in atmospheric CO2 concentrations. For the study area climate change scenarios are characterized by an increase in CO2 concentrations, temperature (all season), total precipitation in summer and autumn and by a decrease of total precipitation in spring and winter. Simulations results analyses show an enhancement of the WS3 HJ Andrews Experimental Forest growth (MAI and PAI) in

  17. Western white pine growth relative to forest openings

    Treesearch

    Theresa B. Jain; Russell T. Graham; Penelope Morgan

    2004-01-01

    In northern Rocky Mountains moist forests, timber harvesting, fire exclusion, and an introduced stem disease have contributed to the decline in western white pine (Pinus monticola Dougl. ex D. Don) abundance (from 90% to 10% of the area). Relations between canopy openings (0.1-15 ha) and western white pine growth within different physical settings are identified....

  18. Similar biodiversity of ectomycorrhizal fungi in set-aside plantations and ancient old-growth broadleaved forests

    PubMed Central

    Spake, Rebecca; van der Linde, Sietse; Newton, Adrian C.; Suz, Laura M.; Bidartondo, Martin I.; Doncaster, C. Patrick

    2016-01-01

    Setting aside overmature planted forests is currently seen as an option for preserving species associated with old-growth forests, such as those with dispersal limitation. Few data exist, however, on the utility of set-aside plantations for this purpose, or the value of this habitat type for biodiversity relative to old-growth semi-natural ecosystems. Here, we evaluate the contribution of forest type relative to habitat characteristics in determining species richness and composition in seven forest blocks, each containing an ancient old-growth stand (> 1000 yrs) paired with a set-aside even-aged planted stand (ca. 180 yrs). We investigated the functionally important yet relatively neglected ectomycorrhizal fungi (EMF), a group for which the importance of forest age has not been assessed in broadleaved forests. We found that forest type was not an important determinant of EMF species richness or composition, demonstrating that set-aside can be an effective option for conserving ancient EMF communities. Species richness of above-ground EMF fruiting bodies was principally related to the basal area of the stand (a correlate of canopy cover) and tree species diversity, whilst richness of below-ground ectomycorrhizae was driven only by tree diversity. Our results suggest that overmature planted forest stands, particularly those that are mixed-woods with high basal area, are an effective means to connect and expand ecological networks of ancient old-growth forests in historically deforested and fragmented landscapes for ectomycorrhizal fungi. PMID:26917858

  19. Short-term effects of experimental burning and thinning on soil respiration in an old-growth, mixed-conifer forest

    Treesearch

    Siyan Ma; Jiquan Chen; Malcolm North; Heather E. Erickson; Mary Bresee; James Le Moine

    2004-01-01

    To understand the roles of forest management practices in meeting the goals of forest sustainability and CO2 sequestration, we evaluated the effects of burning and thinning treatments on soil respiration and soil environments in an old-growth, mixed-conifer forest in California’s southern Sierra Nevada. Six experimental treatments with two levels...

  20. [Evaluation of forest ecosystem services value in Liaoning Province].

    PubMed

    Wang, Bing; Lu, Shao-wei; You, Wen-zhong; Ren, Xiao-xu; Xing, Zhao-kai; Wang, Shi-ming

    2010-07-01

    Based on the long-term located observation of forest ecosystem, and by using the 2006 forest resources inventory data of Liaoning Province and the forest industry standard of the People's Republic of China( LY/T 1721-2008, specification for assessment of forest ecosystem services in China), an evaluation was made on the material quantity and services value of main forest ecosystems in fourteen cities of Liaoning Province. In this province, the forest ecosystem services value supplied by water storage, soil conservation, C fixation, O2 release, nutrients accumulation, environment purification, biodiversity conservation, and forest recreation in 2006 was 2591.72 x 10(8) yuan, which was 8.54 times of the forestry production value and 28.02% in the GDP of the province. The services value of water storage, biodiversity conservation, C fixation, and O2 release occupied 79.09% of the total, being the main forest ecosystem services in the province. Economic forest and shrub had smaller per unit services value but larger area, and hence, their ecosystem services value should not be ignored. Abies fargesii forest, Phellodendron amurense forest, Juglans mandshurica forest, and Fraxinus mandshurica forest were the representative zonal vegetations in Liaoning Province, which had high value in biodiversity conservation. Under the effects of climate and other factors, the forest area and forest quality in west Liaoning were lower than those in east Liaoning.

  1. [Evaluation on sustainability of forest resources in Bailong River forest region, Gansu Province].

    PubMed

    Guo, Zhenggang; Cheng, Guodong; Wu, Bingli; Chen, Yuqi; Sun, Xuegang

    2003-09-01

    Based on the theories of sustainable development of forest resources, this paper constructed an index system for the integrative evaluation on the sustainability of forest resources in Bailon River forest region of Gansu Province. After calculated the index values of five strategic levels and twenty measure levels, the degree of harmony (DH) was obtained, with which, the sustainability of test forest resources could be evaluated. The DH value was 0.5320 in 1996 and 0.6100 in 2000, which was smaller than the theoretic value of 0.7000, and hence, this forest region belonged to non-sustainable development, but made some progress for its sustainability.

  2. Communicating old-growth forest management on the Allegheny National Forest

    Treesearch

    Brad Nelson; Chris Nowak; Scott Reitz; Dave deCalesta; Steve Wingate

    1997-01-01

    Successful communication of old-growth management, including the role of silviculture, is achieved by integrating as a working whole the topics addressed in this workshop. We have used research, technology transfer and adaptive management to achieve this integration on the Allegheny National Forest. Program success depends on scientists and practitioners working...

  3. Tree growth and competition in an old-growth Picea abies forest of boreal Sweden: influence of tree spatial patterning

    USGS Publications Warehouse

    Fraver, Shawn; D'Amato, Anthony W.; Bradford, John B.; Jonsson, Bengt Gunnar; Jönsson, Mari; Esseen, Per-Anders

    2013-01-01

    Question: What factors best characterize tree competitive environments in this structurally diverse old-growth forest, and do these factors vary spatially within and among stands? Location: Old-growth Picea abies forest of boreal Sweden. Methods: Using long-term, mapped permanent plot data augmented with dendrochronological analyses, we evaluated the effect of neighbourhood competition on focal tree growth by means of standard competition indices, each modified to include various metrics of trees size, neighbour mortality weighting (for neighbours that died during the inventory period), and within-neighbourhood tree clustering. Candidate models were evaluated using mixed-model linear regression analyses, with mean basal area increment as the response variable. We then analysed stand-level spatial patterns of competition indices and growth rates (via kriging) to determine if the relationship between these patterns could further elucidate factors influencing tree growth. Results: Inter-tree competition clearly affected growth rates, with crown volume being the size metric most strongly influencing the neighbourhood competitive environment. Including neighbour tree mortality weightings in models only slightly improved descriptions of competitive interactions. Although the within-neighbourhood clustering index did not improve model predictions, competition intensity was influenced by the underlying stand-level tree spatial arrangement: stand-level clustering locally intensified competition and reduced tree growth, whereas in the absence of such clustering, inter-tree competition played a lesser role in constraining tree growth. Conclusions: Our findings demonstrate that competition continues to influence forest processes and structures in an old-growth system that has not experienced major disturbances for at least two centuries. The finding that the underlying tree spatial pattern influenced the competitive environment suggests caution in interpreting traditional tree

  4. Conserving old-growth forest diversity in disturbance-prone landscapes.

    Treesearch

    Thomas A. Spies; Miles A. Hemstrom; Andrew Youngblood; Susan. Hummel

    2006-01-01

    A decade after its creation, the Northwest Forest Plan is contributing to the conservation of old growth forests on federal land. However, the success and outlook for the plan are questionable in the dry provinces, where losses of old growth to wildfire have been relatively high and risks of further loss remain. We summarize the state of knowledge of old-growth forests...

  5. Changes in conifer and deciduous forest foliar and forest floor chemistry and basal area tree growth across a nitrogen (N) deposition gradient in the northeastern US

    Treesearch

    Johnny L. Boggs; Steven G. McNulty; Linda H. Pardo

    2007-01-01

    We evaluated foliar and forest floor chemistry across a gradient of N deposition in the Northeast at 11 red spruce (Picea rubens Sarg.) sites in 1987/1988 and foliar and forest floor chemistry and basal area growth at six paired spruce and deciduous sites in 1999. The six red spruce plots were a subset of the original 1987/1988 spruce sites. In 1999...

  6. Classification and evaluation for forest sites in the Cumberland Mountains

    Treesearch

    Glendon W. Smalley

    1984-01-01

    This report classifies and evaluates forest sites in the Cumberland Mountains (fig. 1) for the management of several commercially valuable tree species. It provides forest managers with a land classification system that will enable them to subdivide forest land into logical segments (landtypes), allow them to rate productivity, and alert them to any limitations and...

  7. Basal area growth impacts of dwarf misletoe on western hemlock in an old-growth forest

    Treesearch

    David C. Shaw; Huso Manuela; Howard Bruner

    2008-01-01

    We investigated the effect of western hemlock dwarf mistletoe (Arceuthobium tsugense (Rosend.) G.N. Jones ssp. tsugense) on the 13-year basal area growth of large (>45.7 cm diameter at breast height) western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees in an old-growth forest in southwestern Washington...

  8. Uncertainty about future nitrogen availability dominates boreal forest growth projections

    NASA Astrophysics Data System (ADS)

    Mäkelä, Annikki; Kalliokoski, Tuomo; Peltoniemi, Mikko

    2015-04-01

    There is broad consensus among scientists that the capacity of forests in the boreal zone to take up carbon will increase as a result of climate change. However, boreal forests are strongly nitrogen limited. This may hamper the potential increase in GPP for forest productivity and carbon sequestration, but little is known about the impact of climate change on nitrogen availability in forests. Here we use OptiPipe, a model of optimal carbon and nitrogen co-allocation to analyse the role of nitrogen availability in growth limitation under climate change in Finland. We predict changes in metabolic rates related to the C balance using existing models and data, and we explore three alternative, plausible scenarios of N availability under climate change. Three climate scenarios based on three SRES emissions scenarios - B1 (low), A1B (moderate) and A2 (high) - are used for projecting changes of daily temperature, precipitation, vapour pressure deficit and solar radiation for periods 2011-2040, 2041-2070 and 2071-2100. We use a mean among 8 climate models. CO2 concentrations corresponding to the SRES scenarios come from (IPCC, 2007: Climate Change 2007: The Physical Science Basis) The results will be presented across Finland on a 10 km x 10 km grid. The results indicate that NPP and woody growth will increase under climate change if N availability is also increasing. If N availability is limited, volume growth will to reduce, because maintenance costs (respiration and turnover) increase. If N availability increases relatively as much or more than C availability, reduced allocation requirements to fine roots will lead to more foliage with higher photosynthetic capacity, thus increasing woody volume growth disproportionately. These results are attributable to optimised carbon and nitrogen co-allocation. In order to reduce the uncertainty of growth predictions, a better understanding of the mechanisms related to N availability is needed.

  9. Pervasive growth reduction in Norway spruce forests following wind disturbance.

    PubMed

    Seidl, Rupert; Blennow, Kristina

    2012-01-01

    In recent decades the frequency and severity of natural disturbances by e.g., strong winds and insect outbreaks has increased considerably in many forest ecosystems around the world. Future climate change is expected to further intensify disturbance regimes, which makes addressing disturbances in ecosystem management a top priority. As a prerequisite a broader understanding of disturbance impacts and ecosystem responses is needed. With regard to the effects of strong winds--the most detrimental disturbance agent in Europe--monitoring and management has focused on structural damage, i.e., tree mortality from uprooting and stem breakage. Effects on the functioning of trees surviving the storm (e.g., their productivity and allocation) have been rarely accounted for to date. Here we show that growth reduction was significant and pervasive in a 6.79 million hectare forest landscape in southern Sweden following the storm Gudrun (January 2005). Wind-related growth reduction in Norway spruce (Picea abies (L.) Karst.) forests surviving the storm exceeded 10% in the worst hit regions, and was closely related to maximum gust wind speed (R(2) = 0.849) and structural wind damage (R(2) = 0.782). At the landscape scale, wind-related growth reduction amounted to 3.0 million m(3) in the three years following Gudrun. It thus exceeds secondary damage from bark beetles after Gudrun as well as the long-term average storm damage from uprooting and stem breakage in Sweden. We conclude that the impact of strong winds on forest ecosystems is not limited to the immediately visible area of structural damage, and call for a broader consideration of disturbance effects on ecosystem structure and functioning in the context of forest management and climate change mitigation.

  10. Pervasive Growth Reduction in Norway Spruce Forests following Wind Disturbance

    PubMed Central

    Seidl, Rupert; Blennow, Kristina

    2012-01-01

    Background In recent decades the frequency and severity of natural disturbances by e.g., strong winds and insect outbreaks has increased considerably in many forest ecosystems around the world. Future climate change is expected to further intensify disturbance regimes, which makes addressing disturbances in ecosystem management a top priority. As a prerequisite a broader understanding of disturbance impacts and ecosystem responses is needed. With regard to the effects of strong winds – the most detrimental disturbance agent in Europe – monitoring and management has focused on structural damage, i.e., tree mortality from uprooting and stem breakage. Effects on the functioning of trees surviving the storm (e.g., their productivity and allocation) have been rarely accounted for to date. Methodology/Principal Findings Here we show that growth reduction was significant and pervasive in a 6.79·million hectare forest landscape in southern Sweden following the storm Gudrun (January 2005). Wind-related growth reduction in Norway spruce (Picea abies (L.) Karst.) forests surviving the storm exceeded 10% in the worst hit regions, and was closely related to maximum gust wind speed (R2 = 0.849) and structural wind damage (R2 = 0.782). At the landscape scale, wind-related growth reduction amounted to 3.0 million m3 in the three years following Gudrun. It thus exceeds secondary damage from bark beetles after Gudrun as well as the long-term average storm damage from uprooting and stem breakage in Sweden. Conclusions/Significance We conclude that the impact of strong winds on forest ecosystems is not limited to the immediately visible area of structural damage, and call for a broader consideration of disturbance effects on ecosystem structure and functioning in the context of forest management and climate change mitigation. PMID:22413012

  11. Identifying ontogenetic, environmental and individual components of forest tree growth

    PubMed Central

    Chaubert-Pereira, Florence; Caraglio, Yves; Lavergne, Christian; Guédon, Yann

    2009-01-01

    Background and Aims This study aimed to identify and characterize the ontogenetic, environmental and individual components of forest tree growth. In the proposed approach, the tree growth data typically correspond to the retrospective measurement of annual shoot characteristics (e.g. length) along the trunk. Methods Dedicated statistical models (semi-Markov switching linear mixed models) were applied to data sets of Corsican pine and sessile oak. In the semi-Markov switching linear mixed models estimated from these data sets, the underlying semi-Markov chain represents both the succession of growth phases and their lengths, while the linear mixed models represent both the influence of climatic factors and the inter-individual heterogeneity within each growth phase. Key Results On the basis of these integrative statistical models, it is shown that growth phases are not only defined by average growth level but also by growth fluctuation amplitudes in response to climatic factors and inter-individual heterogeneity and that the individual tree status within the population may change between phases. Species plasticity affected the response to climatic factors while tree origin, sampling strategy and silvicultural interventions impacted inter-individual heterogeneity. Conclusions The transposition of the proposed integrative statistical modelling approach to cambial growth in relation to climatic factors and the study of the relationship between apical growth and cambial growth constitute the next steps in this research. PMID:19684021

  12. Multicriteria evaluation of simulated logging scenarios in a tropical rain forest.

    PubMed

    Huth, Andreas; Drechsler, Martin; Köhler, Peter

    2004-07-01

    Forest growth models are useful tools for investigating the long-term impacts of logging. In this paper, the results of the rain forest growth model FORMIND were assessed by a multicriteria decision analysis. The main processes covered by FORMIND include tree growth, mortality, regeneration and competition. Tree growth is calculated based on a carbon balance approach. Trees compete for light and space; dying large trees fall down and create gaps in the forest. Sixty-four different logging scenarios for an initially undisturbed forest stand at Deramakot (Malaysia) were simulated. The scenarios differ regarding the logging cycle, logging method, cutting limit and logging intensity. We characterise the impacts with four criteria describing the yield, canopy opening and changes in species composition. Multicriteria decision analysis was used for the first time to evaluate the scenarios and identify the efficient ones. Our results plainly show that reduced-impact logging scenarios are more 'efficient' than the others, since in these scenarios forest damage is minimised without significantly reducing yield. Nevertheless, there is a trade-off between yield and achieving a desired ecological state of logged forest; the ecological state of the logged forests can only be improved by reducing yields and enlarging the logging cycles. Our study also demonstrates that high cutting limits or low logging intensities cannot compensate for the high level of damage caused by conventional logging techniques.

  13. Basal area growth for 15 tropical trees species in Puerto Rico. Forest

    Treesearch

    B. R. Parresol

    1995-01-01

    The tabonuco forest of Puerto Rico support a diverse population of tree species valued for timber, fuel, food, wildlife food and cover, and erosion control among other use. tree basal area growth data spanning 39 years are avaible on 15 species from eigth permanent plots in Luquillo Experimental Forest. The complexity of the rain forest challeges current forest...

  14. Benchmark carbon stocks from old-growth forests in northern New England, USA

    Treesearch

    Coeli M. Hoover; William B. Leak; Brian G. Keel

    2012-01-01

    Forests world-wide are recognized as important components of the global carbon cycle. Carbon sequestration has become a recognized forest management objective, but the full carbon storage potential of forests is not well understood. The premise of this study is that old-growth forests can be expected to provide a reasonable estimate of the upper limits of carbon...

  15. An Old-Growth Definition for Evergreen Bay Forests and Related Seral Communities

    Treesearch

    Martha R. McKevlin

    1996-01-01

    This document describes old-growth conditions in an evergreen bay forest stand. Bay forests occur throughout the Atlantic and Gulf Coastal Plains. However, they are considered rare and are present across the landscape in a patchwork mosaic with other forest types in various stages of succession. Bay forests can be found associated with pocosins, Carolina bays and...

  16. Forest Fire Prevention Programs and Their Evaluation In U.S. Forest Service Region 8

    Treesearch

    G. Richard Wetherill

    1982-01-01

    A telephone survey of all national forest ranger districts in Region 8 obtained data describing the status of forest fire prevention program evaluation. Out of the 396 programs being conducted on the 105 districts in the South, only one program had undergone any sort of systematic evaluation. Survey data indicate that ranger district prevention personnel are aware of...

  17. Contrasting growth phenology of native and invasive forest shrubs mediated by genome size.

    PubMed

    Fridley, Jason D; Craddock, Alaä

    2015-08-01

    Examination of the significance of genome size to plant invasions has been largely restricted to its association with growth rate. We investigated the novel hypothesis that genome size is related to forest invasions through its association with growth phenology, as a result of the ability of large-genome species to grow more effectively through cell expansion at cool temperatures. We monitored the spring leaf phenology of 54 species of eastern USA deciduous forests, including native and invasive shrubs of six common genera. We used new measurements of genome size to evaluate its association with spring budbreak, cell size, summer leaf production rate, and photosynthetic capacity. In a phylogenetic hierarchical model that differentiated native and invasive species as a function of summer growth rate and spring budbreak timing, species with smaller genomes exhibited both faster growth and delayed budbreak compared with those with larger nuclear DNA content. Growth rate, but not budbreak timing, was associated with whether a species was native or invasive. Our results support genome size as a broad indicator of the growth behavior of woody species. Surprisingly, invaders of deciduous forests show the same small-genome tendencies of invaders of more open habitats, supporting genome size as a robust indicator of invasiveness.

  18. Nutrient status and plant growth effects of forest soils in the Basin of Mexico.

    PubMed

    Fenn, M E; Perea-Estrada, V M; de Bauer, L I; Pérez-Suárez, M; Parker, D R; Cetina-Alcalá, V M

    2006-03-01

    The nutrient status of forest soils in the Mexico City Air Basin was evaluated by observing plant growth responses to fertilization with N, P or both nutrients combined. P deficiency was the most frequent condition for soil from two high pollution sites and N deficiency was greatest at a low N deposition site. Concentrations of Pb and Ni, and to a lesser extent Zn and Co, were higher at the high pollution sites. However, positive plant growth responses to P and sometimes to N, and results of wheat root elongation bioassays, suggest that heavy metal concentrations were not directly phytotoxic. Further studies are needed to determine if heavy metal toxicity to mycorrhizal symbionts of eucalyptus (Eucalyptus camaldulensis Dehnh.) from high pollution sites may explain the P deficiency and stunted growth. P deficiency is expected to limit the capacity for biotic N retention in N saturated forested watersheds in the Basin of Mexico dominated by Andisols.

  19. Coupled forest growth-hydrology modelling as an instrument for the assessment of effects of forest management on hydrology in forested catchments

    NASA Astrophysics Data System (ADS)

    Sutmöller, J.; Hentschel, S.; Hansen, J.; Meesenburg, H.

    2011-03-01

    The type and intensity of forest management directly influences regional catchment hydrology. Future forest management must optimise the effects of its practices to achieve sustainable management. With scenario analysis of forestry practices, the effects of different forest utilisation strategies on the hydrology of forested catchments can be temporally and spatially quantified. The approach adopted in this study necessitated the development of an interactive system for the spatially distributed modelling of hydrology in relation to forest stand development. Consequently, a forest growth model was used to simulate stand development assuming various forest management activities. Selected simulated forest growth parameters were entered into the hydrological model to simulate water fluxes under different conditions of forest structure. The approach enables the spatially differentiated quantification of changes in the water regime (e.g. increased evapotranspiration). The results of hydrological simulations in the study area, the Oker catchment (northern Harz Mountains), show that forests contribute to the protection of water systems because they have a balancing effect on the hydrological regime. As scenario simulations also suggest, however, forestry practices can also lead to substantial changes in water budgets of forested catchments. The preservation of the hydrological services of forests requires a sustainable and long-term forest conversion on the basis of current management directives for near natural silviculture. Management strategies on basis of moderate harvesting regimes are preferred because of their limited impact on the water budget.

  20. An Old-Growth Definition for Red River Bottom Forests in the Eastern United States

    Treesearch

    Ted Shear; Mike Young; Robert Kellison

    1997-01-01

    Our goal was to develop a description of old-growth red river bottom forests of the Southeastern United States. We compared the characteristics of forests described in the scientific literature and forests we examined to various published criteria for old-growth condition. Because red rivers are a relatively new landscape feature (most 250 years old, resulting from...

  1. Old forests and endangered woodpeckers: old-growth in the Southern Coastal Plain

    Treesearch

    Robert Mitchell; Todd Engstrom; Rebecca Sharitz; Diane De Steven; Kevin Hiers; Robert Cooper; Katherine. Kirkman

    2009-01-01

    Southern old-growth forests are small and rare, but critical in their support of biodiversity. While the remnant old-growth forests contain diversity that is significant regionally and globally, they most likely represent only a portion of the variety that old forests once sustained. High within-habitat diversity and rarity in the landscape magnify the conservation...

  2. Spatial variability in forest growth—climate relationships in the Olympic Mountains, Washington.

    Treesearch

    Jill M. Nakawatase; David L. Peterson

    2006-01-01

    For many Pacific Northwest forests, little is known about the spatial and temporal variability in tree growth - climate relationships, yet it is this information that is needed to predict how forests will respond to future climatic change. We studied the effects of climatic variability on forest growth at 74 plots in the western and northeastern Olympic Mountains....

  3. Old-growth definition for western and mixed mesophytic forests. Forest Service general technical report

    SciTech Connect

    Greenberg, C.H.; McLeod, D.E.; Loftis, D.L.

    1997-09-01

    Old-growth mixed and western mesophytic forest characteristics may include high canopy species diversity; uneven-age and size distribution, including several old, decadent, large-diameter tree per hectare; low density and high basal area of canopy trees; and multiple vegetation strata. Additional indicators include the presence of snags and logs in several size and decomposition classes; undisturbed soil with no compaction, well-developed organic layer and soil macropores; and tree-fall gaps of various sizes and ages.

  4. Nutrient status and plant growth effects of forest soils in the Basin of Mexico

    Treesearch

    Mark E. Fenn; V.M. Perea-Estrada; L.I. de Bauer; M. Pérez-Suárez; D.R. Parker; V.M. Cetina-Alcalá

    2006-01-01

    The nutrient status of forest soils in the Mexico City Air Basin was evaluated by observing plant growth responses to fertilization with N, P or both nutrients combined. P deficiency was the most frequent condition for soil from two high pollution sites and N deficiency was greatest at a low N deposition site. Concentrations of Pb and Ni, and to a lesser extent Zn and...

  5. Relationships Between Shallow Groundwater and Tree Growth in a Northern Wisconsin Forest

    NASA Astrophysics Data System (ADS)

    Ciruzzi, D. M.; Steven, L. I.

    2015-12-01

    As drought variability increases across forests in the United States, it is critical to evaluate ecosystem attributes that reduce drought vulnerability. Groundwater has been shown to sustain tree growth and transpiration in arid and semi-arid ecosystems during drought, yet this relationship has yet to be extensively explored in mesic environments. This research aims to investigate groundwater-tree interactions in a north temperate forest in northern Wisconsin with attention to drought stress. We question if trees in areas of shallow groundwater with lower inter-annual variability will have higher and more consistent tree growth rates during drought conditions. Historic water table measurements monitored in the Trout Lake watershed include a decline in groundwater levels by ~1 m caused by a prolonged drought from 2006-2013. Within the watershed, we examined tree growth response between wet and dry years across sites covering a 1-9 m depth to groundwater gradient over the past 30 years. Combined with remotely sensed vegetation indices and tree core chronologies, we show regions and individual trees influenced by groundwater depth variability, respectively. Generally, vegetation indices and tree growth rates were higher during years of shallower spring and summer groundwater. By exploring the influences of shallow groundwater on tree growth in temperate forests, groundwater conferred drought resistance may be mapped for sustainable management.

  6. Old-growth definition for Red River bottom forests in the eastern United States. Forest Service general technical report

    SciTech Connect

    Shear, T.; Young, M.; Kellison, R.

    1997-05-01

    Our goal was to develop a description of old-growth red river bottom forests of the Southeastern United States. We compared the characteristics of forests described in the scientific literature and forests we examined to various published criteria for old-growth condition. Because red rivers are a relatively new landscape feature (most < 250 years old, resulting from human-induced soil erosion) and because dramatic changes to their floodplains continue to occur, we do not believe that any old-growth red river forests exist. All the stands along these rivers present at European settlement have been cut and/or otherwise severely altered. In the dynamic landscape after settlement, there have been no opportunities for new old-growth forests to develop. Stands older than 50 to 60 years are rare. Therefore, we propose a stand condition called older growth and list the characteristics. With time and stable site conditions, we believe that old-growth and red river forests can develop from older-growth forests.

  7. Climate indices strongly influence old-growth forest carbon exchange

    SciTech Connect

    Wharton, Sonia; Falk, Matthias

    2016-04-13

    We present a decade and a half (1998–2013) of carbon dioxide fluxes from an old-growth stand in the American Pacific Northwest to identify ecosystem-level responses to Pacific teleconnection patterns, including the El Niño/Southern Oscillation (ENSO). This study provides the longest, continuous record of old-growth eddy flux data to date from one of the longest running Fluxnet stations in the world. From 1998 to 2013, average annual net ecosystem exchange (FNEE) at Wind River AmeriFlux was –32 ± 84 g C m–2 yr–1 indicating that the late seral forest is on average a small net sink of atmospheric carbon. However, interannual variability is high (>300 g C m–2 yr–1) and shows that the stand switches from net carbon sink to source in response to climate drivers associated with ENSO. The old-growth forest is a much stronger sink during La Niña years (mean FNEE = –90 g C m–2 yr–1) than during El Niño when the stand turns carbon neutral or into a small net carbon source (mean FNEE = +17 g C m–2 yr–1). Forest inventory data dating back to the 1930s show a similar correlation with the lower frequency Pacific North American (PNA) and Pacific Decadal Oscillation (PDO) whereby higher aboveground net primary productivity (FANPP) is associated with cool phases of both the PNA and PDO. Furthermore, these measurements add evidence that carbon exchange in old-growth stands may be more sensitive to climate variability across shorter time scales than once thought.

  8. Climate indices strongly influence old-growth forest carbon exchange

    DOE PAGES

    Wharton, Sonia; Falk, Matthias

    2016-04-13

    We present a decade and a half (1998–2013) of carbon dioxide fluxes from an old-growth stand in the American Pacific Northwest to identify ecosystem-level responses to Pacific teleconnection patterns, including the El Niño/Southern Oscillation (ENSO). This study provides the longest, continuous record of old-growth eddy flux data to date from one of the longest running Fluxnet stations in the world. From 1998 to 2013, average annual net ecosystem exchange (FNEE) at Wind River AmeriFlux was –32 ± 84 g C m–2 yr–1 indicating that the late seral forest is on average a small net sink of atmospheric carbon. However, interannualmore » variability is high (>300 g C m–2 yr–1) and shows that the stand switches from net carbon sink to source in response to climate drivers associated with ENSO. The old-growth forest is a much stronger sink during La Niña years (mean FNEE = –90 g C m–2 yr–1) than during El Niño when the stand turns carbon neutral or into a small net carbon source (mean FNEE = +17 g C m–2 yr–1). Forest inventory data dating back to the 1930s show a similar correlation with the lower frequency Pacific North American (PNA) and Pacific Decadal Oscillation (PDO) whereby higher aboveground net primary productivity (FANPP) is associated with cool phases of both the PNA and PDO. Furthermore, these measurements add evidence that carbon exchange in old-growth stands may be more sensitive to climate variability across shorter time scales than once thought.« less

  9. Converging Climate Sensitivities of European Forests Between Observed Radial Tree Growth and Vegetation Models

    NASA Technical Reports Server (NTRS)

    Zhang, Zhen; Babst, Flurin; Bellassen, Valentin; Frank, David; Launois, Thomas; Tan, Kun; Ciais, Philippe; Poulter, Benjamin

    2017-01-01

    The impacts of climate variability and trends on European forests are unevenly distributed across different bioclimatic zones and species. Extreme climate events are also becoming more frequent and it is unknown how they will affect feed backs of CO2 between forest ecosystems and the atmosphere. An improved understanding of species differences at the regional scale of the response of forest productivity to climate variation and extremes is thus important for forecasting forest dynamics. In this study, we evaluate the climate sensitivity of above ground net primary production (NPP) simulated by two dynamic global vegetation models (DGVM; ORCHIDEE and LPJ-wsl) against tree ring width (TRW) observations from about1000 sites distributed across Europe. In both the model simulations and the TRW observations, forests in northern Europe and the Alps respond positively to warmer spring and summer temperature, and their overall temperature sensitivity is larger than that of the soil-moisture-limited forests in central Europe and Mediterranean regions. Compared with TRW observations, simulated NPP from ORCHIDEE and LPJ-wsl appear to be overly sensitive to climatic factors. Our results indicate that the models lack biological processes that control time lags, such as carbohydrate storage and remobilization, that delay the effects of radial growth dynamics to climate. Our study highlights the need for re-evaluating the physiological controls on the climate sensitivity of NPP simulated by DGVMs. In particular, DGVMs could be further enhanced by a more detailed representation of carbon reserves and allocation that control year-to year variation in plant growth.

  10. Growth of Secondary Forest in Puerto Rico Between 1980 and 1985.

    Treesearch

    P. L. Weaver; R. A. Birdsey

    1990-01-01

    Successive inventories in Puerto Rico provided the first estimates of secondary forest growth on a regional basis. The volume of growing stock trees increased by 32%, and timber volume by nearly 36%, on all classes of forest land between 1980 and 198.5. Timber volume growth rates (in m’ha-’ yr-’ ) varied by forest class and averaged 2.0 in young secondary forest, 6.9...

  11. Two decades of stability and change in old-growth forest at Mount Rainier National Park.

    Treesearch

    Steven A. Acker; Jerry F. Franklin; Sarah E. Greene; Ted B. Thomas; Robert Van Pelt; Kenneth J. Bible

    2006-01-01

    We examined how composition and structure of old-growth and mature forests at Mount Rainier National Park changed between the mid-1970s and mid-1990s. We assessed whether the patterns of forest dynamics observed in lower elevation old-growth forests in the Pacific Northwest held true for the higher-elevation forests of the Park. We used measurements of tree recruitment...

  12. Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink.

    PubMed

    McGarvey, Jennifer C; Thompson, Jonathan R; Epstein, Howard E; Shugart, Herman H

    2015-02-01

    Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come.

  13. Structure and development of old-growth, unmanaged second-growth, and extended rotation Pinus resinosa forests in Minnesota, USA

    Treesearch

    Emily J. Silver; Anthony W. D' Amato; Shawn Fraver; Brian J. Palik; John B. Bradford

    2013-01-01

    The structure and developmental dynamics of old-growth forests often serve as important baselines for restoration prescriptions aimed at promoting more complex structural conditions in managed forest landscapes. Nonetheless, long-term information on natural patterns of development is rare for many commercially important and ecologically widespread forest types....

  14. [Evaluation of economic forest ecosystem services in China].

    PubMed

    Wang, Bing; Lu, Shao-Wei

    2009-02-01

    This paper quantitatively evaluated the economic forest ecosystem services in the provinces of China in 2003, based on the long-term and continuous observations of economic forest ecosystems in this country, the sixth China national forest resources inventory data, and the price parameter data from the authorities in the world, and by applying the law of market value, the method of substitution of the expenses, and the law of the shadow project. The results showed that in 2003, the total value of economic forest ecosystem services in China was 11763.39 x 10(8) yuan, and the total value of the products from economic forests occupied 19.3% of the total ecosystem services value, which indicated that the economic forests not only provided society direct products, but also exhibited enormous eco-economic value. The service value of the functions of economic forests was in the order of water storage > C fixation and O2 release > biodiversity conservation > erosion control > air quality purification > nutrient cycle. The spatial pattern of economic forest ecosystem services in the provinces of China had the same trend with the spatial distribution of water and heat resources and biodiversity. To understand the differences of economic forest ecosystem services in the provinces of China was of significance in alternating the irrational arrangement of our present forestry production, diminishing the abuses of forest management, and establishing high grade, high efficient, and modernized economic forests.

  15. Complementary models of tree species-soil relationships in old-growth temperate forests

    USGS Publications Warehouse

    Cross, Alison; Perakis, Steven S.

    2011-01-01

    Ecosystem level studies identify plant soil feed backs as important controls on soil nutrient availability,particularly for nitrogen and phosphorus. Although site and species specific studies of tree species soil relationships are relatively common,comparatively fewer studies consider multiple coexisting speciesin old-growth forests across a range of sites that vary underlying soil fertility. We characterized patterns in forest floor and mineral soil nutrients associated with four common tree species across eight undisturbed old-growth forests in Oregon, USA, and used two complementary conceptual models to assess tree species soil relationships. Plant soil feedbacks that could reinforce sitelevel differences in nutrient availability were assessed using the context dependent relationships model, where by relative species based differences in each soil nutrient divergedorconvergedas nutrient status changed across sites. Tree species soil relationships that did not reflect strong feedbacks were evaluated using a site independent relationships model, where by forest floor and surface mineral soil nutrient tools differed consistently by tree species across sites,without variation in deeper mineral soils. We found that theorganically cycled elements carbon, nitrogen, and phosphorus exhibited context-dependent differences among species in both forest floor and mineral soil, and most of ten followed adivergence model,where by species differences were greatest at high-nutrient sites. These patterns are consistent with the oryemphasizing biotic control of these elements through plant soil feedback mechanisms. Site independent species differences were strongest for pool so if the weather able cations calcium, magnesium, potassium,as well as phosphorus, in mineral soils. Site independent species differences in forest floor nutrients we reattributable too nespecies that displayed significant greater forest floor mass accumulation. Our finding confirmed that site-independent and

  16. Drought as a driver of declining boreal forest growth: Integrating forest inventory measurements with models to gain insight into underlying mechanisms

    NASA Astrophysics Data System (ADS)

    Trugman, A. T.; Medvigy, D.; Anderegg, W.; Caspersen, J.; Zeng, H.; Pacala, S. W.

    2016-12-01

    Boreal forests contain over 30% of Earth's terrestrial carbon and are an important component of the land carbon sink. However, the future ability of the boreal forest to maintain a net carbon sink is uncertain and depends on potentially compensating interactions of CO2 fertilization, warmer temperatures, and hotter drought conditions. Observational studies have attributed drought as a major driver of recent declines in growth and increases in mortality in many parts of the North American boreal forest. Yet, most vegetation models have a simplistic representation of vegetation water stress and fail to capture drought-associated growth and mortality trends, impacting our ability to accurately forecast the effects of climate change on the boreal forest. Here, we show additional evidence for widespread declines in boreal tree growth and increasing insect-related mortality in aspen trees based on a mixed model analysis of the Cooperative Alaska Forest Inventory. Our findings indicate that the growth decline is controlled by high midsummer potential evapotranspiration that overpowers any CO2 fertilization signal. We also observe a possible shift in the distribution of angiosperm and gymnosperm, a biological transition that could impact long-term local carbon dynamics. Using insight gained from our mixed model analysis, we perform a regional-scale model evaluation using the boreal forest version of Ecosystem Demography model 2 that includes a dynamic soil organic layer, 7 boreal-specific plant functional types, and a fully mechanistic plant hydraulic scheme. We then use both the Alaskan and Canadian Forest Inventories to constrain our hypotheses and assess whether drought related growth declines can be better attributed to tree drought response from (1) carbon starvation, (2) permanent damage of hydraulic machinery, or (3) delayed recovery of hydraulic machinery. Under each of these scenarios we forecast how drought potentially impacts decadal-scale boreal carbon dynamics.

  17. Forest evaporation models: relationships between stand growth and evaporation

    NASA Astrophysics Data System (ADS)

    Le Maitre, D. C.; Versfeld, D. B.

    1997-06-01

    The relationships between forest stand structure, growth and evaporation were analysed to determine whether forest evaporation can be estimated from stand growth data. This approach permits rapid assessment of the potential impacts of afforestation on the water regime. The basis for this approach is (a) that growth rates are determined by water availability and limited by the maximum water extraction potential, and (b) that stand evaporation is proportional to biomass and biomass increment. The relationships between stand growth and evaporation were modelled for a set of catchment experiments where estimates of both growth and evaporation were available. The predicted mean evaporation, over periods of several years, was generally within 10% of the measured mean annual evaporation (rainfall minus streamflow) when the model from one catchment was applied to other catchments planted with the same species. The residual evaporation, after fitting the models, was correlated with rainfall: above-average rainfall resulted in above-average evaporation. This relationship could be used to derive estimates for dry and wet years. Analyses using the models provide additional evidence that Eucalyptus grandis may be depleting groundwater reserves in catchments where its roots can reach the water table. The models are designed to be integrated into a plantation management system which uses a geographic information system for spatial analysis and modelling. The use of readily available growth parameters as predictor variables may reduce our dependence on intricate process-based models. This is seen as an efficient way of extrapolating existing catchment data — reflecting the impacts of forestry on water supplies across a range of sites, climatic zones and species. This approach has the potential for further development, especially in dealing with low flows and faster growing species.

  18. Land-use dynamics influence estimates of carbon sequestration potential in tropical second-growth forest

    NASA Astrophysics Data System (ADS)

    Schwartz, Naomi B.; Uriarte, María; DeFries, Ruth; Gutierrez-Velez, Victor H.; Pinedo-Vasquez, Miguel A.

    2017-07-01

    Many countries have made major commitments to carbon sequestration through reforestation under the Paris Climate Agreement, and recent studies have illustrated the potential for large amounts of carbon sequestration in tropical second-growth forests. However, carbon gains in second-growth forests are threatened by non-permanence, i.e. release of carbon into the atmosphere from clearing or disturbance. The benefits of second-growth forests require long-term persistence on the landscape, but estimates of carbon potential rarely consider the spatio-temporal landscape dynamics of second-growth forests. In this study, we used remotely sensed imagery from a landscape in the Peruvian Amazon to examine patterns of second-growth forest regrowth and permanence over 28 years (1985-2013). By 2013, 44% of all forest cover in the study area was second growth and more than 50% of second-growth forest pixels were less than 5 years old. We modeled probabilities of forest regrowth and clearing as a function of landscape factors. The amount of neighboring forest and variables related to pixel position (i.e. distance to edge) were important for predicting both clearing and regrowth. Forest age was the strongest predictor of clearing probability and suggests a threshold response of clearing probability to age. Finally, we simulated future trajectories of carbon sequestration using the parameters from our models. We compared this with the amount of biomass that would accumulate under the assumption of second-growth permanence. Estimates differed by 900 000 tonnes, equivalent to over 80% of Peru’s commitment to carbon sequestration through ‘community reforestation’ under the Paris Agreement. Though the study area has more than 40 000 hectares of second-growth forest, only a small proportion is likely to accumulate significant carbon. Instead, cycles between forest and non-forest are common. Our results illustrate the importance of considering landscape dynamics when assessing

  19. Effects of selective logging on tropical forest tree growth

    NASA Astrophysics Data System (ADS)

    Figueira, Adelaine Michela E. S.; Miller, Scott D.; de Sousa, Cleilim Albert D.; Menton, Mary C.; Maia, Augusto R.; Da Rocha, Humberto R.; Goulden, Michael L.

    2008-03-01

    We combined measurements of tree growth and carbon dioxide exchange to investigate the effects of selective logging on the Aboveground Live Biomass (AGLB) of a tropical rain forest in the Amazon. Most of the measurements began at least 10 months before logging and continued at least 36 months after logging. The logging removed ˜15% of the trees with Diameter at Breast Height (DBH) greater than 35 cm, which resulted in an instantaneous 10% reduction in AGLB. Both wood production and mortality increased following logging, while Gross Primary Production (GPP) was unchanged. The ratio of wood production to GPP (the wood Carbon Use Efficiency or wood CUE) more than doubled following logging. Small trees (10 cm < DBH < 35 cm) accounted for most of the enhanced wood production. Medium trees (35 cm < DBH < 55 cm) that were within 30 m of canopy gaps created by the logging also showed increased growth. The patterns of enhanced growth are most consistent with logging-induced increases in light availability. The AGLB continued to decline over the study, as mortality outpaced wood production. Wood CUE and mortality remained elevated throughout the 3 years of postlogging measurements. The future trajectory of AGLB and the forest's carbon balance are uncertain, and will depend on how long it takes for heterotrophic respiration, mortality, and CUE to return to prelogging levels.

  20. The effect of size and competition on tree growth rate in old-growth coniferous forests

    USGS Publications Warehouse

    Das, Adrian

    2012-01-01

    Tree growth and competition play central roles in forest dynamics. Yet models of competition often neglect important variation in species-specific responses. Furthermore, functions used to model changes in growth rate with size do not always allow for potential complexity. Using a large data set from old-growth forests in California, models were parameterized relating growth rate to tree size and competition for four common species. Several functions relating growth rate to size were tested. Competition models included parameters for tree size, competitor size, and competitor distance. Competitive strength was allowed to vary by species. The best ranked models (using Akaike’s information criterion) explained between 18% and 40% of the variance in growth rate, with each species showing a strong response to competition. Models indicated that relationships between competition and growth varied substantially among species. The results also suggested that the relationship between growth rate and tree size can be complex and that how we model it can affect not only our ability to detect that complexity but also whether we obtain misleading results. In this case, for three of four species, the best model captured an apparent and unexpected decline in potential growth rate for the smallest trees in the data set.

  1. Forest stand structure and pattern of old-growth western hemlock/Douglas-fir and mixed-conifer forests

    Treesearch

    Malcolm North; Jiquan Chen; Brian Oakley; Bo Song; Mark Rudnicki; Andrew Gray; Jim Innes

    2004-01-01

    With fire suppression, many western forests are expected to have fewer gaps and higher stem density of shade-tolerant species as light competition becomes a more significant influence on stand pattern and composition. We compared species composition, structure, spatial pattern, and environmental factors such as light and soil moisture between two old-growth forests:...

  2. Spatially random mortality in old-growth red pine forests of northern Minnesota

    Treesearch

    Tuomas ​Aakala; Shawn Fraver; Brian J. Palik; Anthony W. D' Amato

    2012-01-01

    Characterizing the spatial distribution of tree mortality is critical to understanding forest dynamics, but empirical studies on these patterns under old-growth conditions are rare. This rarity is due in part to low mortality rates in old-growth forests, the study of which necessitates long observation periods, and the confounding influence of tree in-growth during...

  3. Area of old-growth forests in California, Oregon, and Washington.

    Treesearch

    Charles L. Bolsinger; Karen L. Waddell

    1993-01-01

    Area of old-growth forests in California, Oregon, and Washington has declined significantly in the second half of the 20th century. This report summarizes available information on old-growth forest area by ownership in California, Oregon, and Washington. Old-growth definitions used by the various owners and agencies are provided.

  4. Adjusting the Stems Regional Forest Growth Model to Improve Local Predictions

    Treesearch

    W. Brad Smith

    1983-01-01

    A simple procedure using double sampling is described for adjusting growth in the STEMS regional forest growth model to compensate for subregional variations. Predictive accuracy of the STEMS model (a distance-independent, individual tree growth model for Lake States forests) was improved by using this procedure

  5. Differences in Townsend's chipmunk populations between second- and old-growth forests in western Oregon

    Treesearch

    D.K. Rosenberg; R.G. Anthony

    1993-01-01

    Because Townsend's chipmunks (Tomias townsendii) may be important in maintaining natural ecosystem processes in forests in the central Oregon Cascade Range, we compared their population characteristics in young second-growth and old-growth forests. We live-trapped Townsend's chipmunks in 5 young (30-60 yr old) second-growth and 5 old-...

  6. Climate-driven speedup of alpine treeline forest growth in the Tianshan Mountains, Northwestern China.

    PubMed

    Qi, Zhaohuan; Liu, Hongyan; Wu, Xiuchen; Hao, Qian

    2015-02-01

    Forest growth is sensitive to interannual climatic change in the alpine treeline ecotone (ATE). Whether the alpine treeline ecotone shares a similar pattern of forest growth with lower elevational closed forest belt (CFB) under changing climate remains unclear. Here, we reported an unprecedented acceleration of Picea schrenkiana forest growth since 1960s in the ATE of Tianshan Mountains, northwestern China by a stand-total sampling along six altitudinal transects with three plots in each transect: one from the ATE between the treeline and the forest line, and the other two from the CFB. All the sampled P. schrenkiana forest patches show a higher growth speed after 1960 and, comparatively, forest growth in the CFB has sped up much slower than that in the ATE. The speedup of forest growth at the ATE is mainly accounted for by climate factors, with increasing temperature suggested to be the primary driver. Stronger water deficit as well as more competition within the CFB might have restricted forest growth there more than that within the ATE, implying biotic factors were also significant for the accelerated forest growth in the ATE, which should be excluded from simulations and predictions of warming-induced treeline dynamics.

  7. Evaluation of forest snow processes models (SnowMKIP2)

    Treesearch

    Nick Rutter; Richard Essery; John Pomeroy; Nuria Altimir; Kostas Andreadis; Ian Baker; Alan Barr; Paul Bartlett; Aaron Boone; Huiping Deng; Herve Douville; Emanuel Dutra; Kelly Elder; others

    2009-01-01

    Thirty-three snowpack models of varying complexity and purpose were evaluated across a wide range of hydrometeorological and forest canopy conditions at five Northern Hemisphere locations, for up to two winter snow seasons. Modeled estimates of snow water equivalent (SWE) or depth were compared to observations at forest and open sites at each location. Precipitation...

  8. Characteristics of remnant old-growth forests in the northern Coast Range of Oregon and comparison to surrounding landscapes.

    Treesearch

    Andrew N. Gray; Vicente J. Monleon; Thomas A. Spies

    2009-01-01

    Old-growth forests provide unique habitat features and landscape functions compared to younger stands. The goals of many forest management plans in the Pacific Northwest include increasing the area of late-successional and old-growth forests. The goal of this study was to describe existing old-growth forests in the northern Oregon Coast Range that might serve as...

  9. Carbon nanotube forests growth using catalysts from atomic layer deposition

    SciTech Connect

    Chen, Bingan; Zhang, Can; Esconjauregui, Santiago; Xie, Rongsi; Zhong, Guofang; Robertson, John; Bhardwaj, Sunil; Cepek, Cinzia

    2014-04-14

    We have grown carbon nanotubes using Fe and Ni catalyst films deposited by atomic layer deposition. Both metals lead to catalytically active nanoparticles for growing vertically aligned nanotube forests or carbon fibres, depending on the growth conditions and whether the substrate is alumina or silica. The resulting nanotubes have narrow diameter and wall number distributions that are as narrow as those grown from sputtered catalysts. The state of the catalyst is studied by in-situ and ex-situ X-ray photoemission spectroscopy. We demonstrate multi-directional nanotube growth on a porous alumina foam coated with Fe prepared by atomic layer deposition. This deposition technique can be useful for nanotube applications in microelectronics, filter technology, and energy storage.

  10. Forest growth modeling and prediction (Volumes 1 & 2).

    Treesearch

    Alan R. Ek; Stephen R. Shifley; Thomas E. Burk

    1988-01-01

    Proceedings of the August 23-27 IUFRO Conference, Minneapolis, Minnesota. Includes 143 manuscripts dealing with growth and yield modeling; regeneration; site characterization; effects of fertilization, genetics, and disturbance; density management; evaluation; estimation; inventory; and application.

  11. Diameter growth of trees in an uneven-aged oak forest in the Missouri Ozarks

    Treesearch

    Edward F. Loewenstein; Paul S. Johnson; Harold E. Garrett

    1997-01-01

    We tested the efficacy of even-aged stand tables for predicting diameter growth of trees in uneven-aged oak stands. The study was based on the age- and diameter-structure of the Pioneer Forest, a 156,000-acre, privately owned oak forest in the Ozark Highlands of Missouri. The forest has been managed by single-tree selection since 1954.

  12. Back to the future: assessing accuracy and sensitivity of a forest growth model

    Treesearch

    Susan Hummel; Paul. Meznarich

    2014-01-01

    The Forest Vegetation Simulator (FVS) is a widely used computer model that projects forest growth and predicts the effects of disturbances such as fire, insects, harvests, or disease. Land managers often use these projections to decide among silvicultural options and estimate the potential effects of these options on forest conditions. Despite FVS's popularity,...

  13. Carbon storage in coarse and fine fractions of Pacific Northwest old-growth forest soils.

    Treesearch

    P.S. Homann; S.M. Remillard; M.E. Harmon; B.T. Bormann

    2004-01-01

    Many assessments of soil C have been restricted to the 2-mm fractions of forest mineral soils. Our objective was to determine the importance of the >2mm fraction to whole-soil C pools in Pacific Northwest old-growth coniferous forests. Seventy-nine pedons in 18 western Washington and Oregon forests were...

  14. Prioritizing treatment of second-growth forests using LiDAR

    Treesearch

    Lathrop P. Leonard; Daryl Van Dyke

    2012-01-01

    We used multi-return light detecting and ranging (LiDAR) to develop a costeffective method for describing forest conditions and prioritizing stands for treatment in over 14,000 ha of second-growth forests (11 to 85 years old) in Del Norte Coast Redwoods State Park (DNCRSP). DNCRSP consists primarily of redwood and Douglas-fir dominated forests with scattered tanoak...

  15. Defining old growth for fire-adapted forests of the Western United States

    Treesearch

    Merrill R. Kaufmann; Daniel Binkley; Peter Z. Fule; Johnson Marlin; Scott L. Stephens; Thomas W. Swetnam

    2007-01-01

    There are varying definitions of old-growth forests because of differences in environment and differing fire influence across the Intermountain West. Two general types of forests reflect the role of fire: 1) forests shaped by natural changes in structure and species makeup-plant succession-that are driven by competitive differences among species and individual trees...

  16. Old-growth Montane Longleaf Pine Forest Age Structure: A Preliminary Assessment

    Treesearch

    J. Morgan Varner; John S. Kush; Ralph S. Meldahl

    1998-01-01

    Presettlement longleaf pine forests of the Southeast have been described as uneven-aged forests comprised of even-aged patches. Less than 4000 ha of old-growth longleaf forest remains. From these few sites remaining, a limited volume of age related literature has evolved, and these studies have been limited to the Lower Coastal Plain physiographic province. This study...

  17. Biomass Accumulation Rates of Amazonian Secondary Forest and Biomass of Old-Growth Forests from Landsat Time Series and GLAS

    NASA Astrophysics Data System (ADS)

    Helmer, E.; Lefsky, M. A.; Roberts, D.

    2009-12-01

    We estimate the age of humid lowland tropical forests in Rondônia, Brazil, from a somewhat densely spaced time series of Landsat images (1975-2003) with an automated procedure, the Threshold Age Mapping Algorithm (TAMA), first described here. We then estimate a landscape-level rate of aboveground woody biomass accumulation of secondary forest by combining forest age mapping with biomass estimates from the Geoscience Laser Altimeter System (GLAS). Though highly variable, the estimated average biomass accumulation rate of 8.4 Mg ha-1 yr-1 agrees well with ground-based studies for young secondary forests in the region. In isolating the lowland forests, we map land cover and general types of old-growth forests with decision tree classification of Landsat imagery and elevation data. We then estimate aboveground live biomass for seven classes of old-growth forest. TAMA is simple, fast, and self-calibrating. By not using between-date band or index differences or trends, it requires neither image normalization nor atmospheric correction. In addition, it uses an approach to map forest cover for the self-calibrations that is novel to forest mapping with satellite imagery; it maps humid secondary forest that is difficult to distinguish from old-growth forest in single-date imagery; it does not assume that forest age equals time since disturbance; and it incorporates Landsat Multispectral Scanner (MSS) imagery. Variations on the work that we present here can be applied to other forested landscapes. Applications that use image time series will be helped by the free distribution of coregistered Landsat imagery, which began in December 2008, and of the Ice Cloud and land Elevation Satellite (ICESat) Vegetation Product, which simplifies the use of GLAS data. Finally, we demonstrate here for the first time how the optical imagery of fine spatial resolution that is viewable on Google Earth provides a new source of reference data for remote sensing applications related to land cover

  18. Calibrating and Evaluating Boomless Spray Systems for Applying Forest Herbicides

    Treesearch

    Michael A. Wehr; Russell W. Johnson; Robert L. Sajdak

    1985-01-01

    Describes a testing procedure used to calibrate and evaluate agricultureal boomless spray systems. Tests allow the user to obtain dependable and satisfactory results when used in actual forest situations.

  19. Classification of forest growth stage using Landsat TM data

    NASA Astrophysics Data System (ADS)

    Fujisaki, Ikuko; Gerard, Patrick D.; Evans, David L.

    2005-09-01

    This study examined the utility of polytomous logistic regression in pixel classification of remotely sensed images by the growth stage of forests. For a population of grouped continuous categories, the assumption of normal distribution of independent variables, which is often required in multivariate classification methods, may not be appropriate. Two types of polytomous logistic regression procedures, multinomial and cumulative logistic regression, were used to classify Landsat TM data by growth stage (regeneration-immature, intermediate, and mature) of loblolly pine (Pinus taeda L.) forest in the east central Mississippi. Multinomial logistic regression is typically used for analysis of unordered categorical data. Cumulative logistic regression is one of the most commonly used methods of ordinal logistic regression which is generally preferred to analyze ordered categorical data, although, it imposes restrictions on the data. Three hundred sample points were located randomly throughout the study site and vectors of pixel values of four bands of Landsat TM data were used to predict growth stage at each sample location. The results were compared to that of parametric and nonparametric discriminant analysis, k-nearest neighbor method. Non-normal distribution of independent variables indicated a violation of the assumptions for parametric discriminant analysis. Classification with cumulative logistic regression using four bands was performed first. However, the assumption of the model was not met. So, the classification was also performed using only band 4 which appeared to meet the assumption. The error rate of cumulative logistic regression was 39.12% with all the bands and 37.70% with band 4 alone. Although error rate with cumulative logistic regression with band 4 alone resulted in the lowest error rate, the improvement over other methods was marginal. The error rate of k-nearest neighbor method varied from 38.68 to 48.06% depending on choice of the value of k.

  20. The Infinite Possible Growth Ambients that Support Single-Wall Carbon Nanotube Forest Growth

    NASA Astrophysics Data System (ADS)

    Kimura, Hiroe; Goto, Jundai; Yasuda, Satoshi; Sakurai, Shunsuke; Yumura, Motoo; Futaba, Don N.; Hata, Kenji

    2013-11-01

    We report the virtually infinite possible carbon feedstocks which support the highly efficient growth of single-wall carbon nanotubes (SWCNTs) using on the water-assisted chemical vapor deposition method. Our results demonstrate that diverse varieties of carbon feedstocks, in the form of hydrocarbons, spanning saturated rings (e.g. trans-deca-hydronaphthalene), saturated chains (e.g. propane), unsaturated rings (e.g. dicyclopentadiene), and unsaturated chains (e.g. ethylene) could be used as a carbon feedstocks with SWCNT forests with heights exceeding 100 ums. Further, we found that all the resultant SWCNTs possessed similar average diameter indicating that the diameter was mainly determined by the catalyst rather than the carbon feedstock within this synthetic system. A demonstration of the generality was the synthesis of a carbon nanotube forest from a highly unorthodox combination of gases where trans-decahydronaphthalene acted as the carbon feedstock and benzaldehyde acted as the growth enhancer.

  1. Implications of mechanistic modeling of drought effects on growth and competition in forest landscape models

    Treesearch

    Eric J. Gustafson; Arjan M. G. De Bruijn; Brian R. Miranda; Brian R. Sturtevant; J. Thompson

    2016-01-01

    The incidence of drought is expected to increase worldwide as a factor structuring forested landscapes. Ecophysiological mechanisms are being added to Forest Landscape Models (FLMs) to increase their robustness to the novel environmental conditions of the future (including drought), but their behavior has not been evaluated for mixed temperate forests. We evaluated...

  2. Evaluation of forest structure, biomass and carbon sequestration in subtropical pristine forests of SW China.

    PubMed

    Nizami, Syed Moazzam; Yiping, Zhang; Zheng, Zheng; Zhiyun, Lu; Guoping, Yang; Liqing, Sha

    2017-03-01

    Very old natural forests comprising the species of Fagaceae (Lithocarpus xylocarpus, Castanopsis wattii, Lithocarpus hancei) have been prevailing since years in the Ailaoshan Mountain Nature Reserve (AMNR) SW China. Within these forest trees, density is quite variable. We studied the forest structure, stand dynamics and carbon density at two different sites to know the main factors which drives carbon sequestration process in old forests by considering the following questions: How much is the carbon density in these forest trees of different DBH (diameter at breast height)? How much carbon potential possessed by dominant species of these forests? How vegetation carbon is distributed in these forests? Which species shows high carbon sequestration? What are the physiochemical properties of soil in these forests? Five-year (2005-2010) tree growth data from permanently established plots in the AMNR was analysed for species composition, density, stem diameter (DBH), height and carbon (C) density both in aboveground and belowground vegetation biomass. Our study indicated that among two comparative sites, overall 54 species of 16 different families were present. The stem density, height, C density and soil properties varied significantly with time among the sites showing uneven distribution across the forests. Among the dominant species, L. xylocarpus represents 30% of the total carbon on site 1 while C. wattii represents 50% of the total carbon on site 2. The average C density ranged from 176.35 to 243.97 t C ha(-1). The study emphasized that there is generous degree to expand the carbon stocking in this AMNR through scientific management gearing towards conservation of old trees and planting of potentially high carbon sequestering species on good site quality areas.

  3. Structural and compositional differences between old-growth and mature second-growth forests in the Missouri Ozarks

    Treesearch

    Stephen R. Shifley; Lynn M. Roovers; Brian L. Brookshire

    1995-01-01

    There are currently only about 7,900 acres (3,200 ha) of remnant old-growth forest in Missouri, but public land management plans call for old-growth acreage to increase to more than 200,000 acres (81,000 ha). To develop a better quantitative understanding of the transitions that are likely as current forests mature to an old-growth state, we compared a number of...

  4. Northwest Forest Plan–the first 15 years (1994–2008): status and trends of late-successional and old-growth forests

    Treesearch

    Melinda Moeur; Janet L. Ohmann; Robert E. Kennedy; Warren B. Cohen; Matthew J. Gregory; Zhiqiang Yang; Heather M. Roberts; Thomas A. Spies; Maria Fiorella

    2011-01-01

    Late-successional and old-growth (LSOG) monitoring characterizes the status and trends of older forests to answer such questions as: How much older forest is there? Where is it? How much has changed and from what causes? Is the Northwest Forest Plan (the Plan) maintaining or restoring older forest ecosystems to desired conditions on federal lands in the Plan area? This...

  5. Information about old growth for selected forest type groups in the eastern United States.

    Treesearch

    Lucy E. Tyrrell; Gregory J. Nowacki; David S. Buckley; Elizabeth A. Nauertz; Jeffrey N. Niese; Jeanette L. Rollinger; John C. Zasada; John C. Zasada

    1998-01-01

    Compiles information about old-growth attributes for nine forest type groups that occur in the eastern United States. A range of values for each old-growth attribute for each forest type is summarized regionally from published and unpublished sources.

  6. Regional distribution and dynamics of coarse woody debris in Midwestern old-growth forests

    Treesearch

    Martin A. Spetich; Stephen R. Shifley; George R. Parker

    1999-01-01

    Old-growth forests have been noted for containing significant quantities of deadwood. However, there has been no coordinated effort to quantify the deadwood component of old-growth remnants across large regions of temperate deciduous forest. We present results of a regional inventory that quantifies and examines regional and temporal trends for deadwood in upland old-...

  7. Growth of Secondary Forest in Puerto Rico Between 1980 and 1985

    Treesearch

    P.L. Weaver; R.A. Birdsey

    1990-01-01

    Successive inventories in Puerto Rico provided the first estimates of secondary forest growth on a regional basis. The volume of growing stock trees increased by 32%, and timber volume by nearly 36%, on all classes of forest land between 1980 and 198.5. Timber volume growth rates (in m3ha-1yr-1 )...

  8. Production, respiration, and overall carbon balance in an old-growth Pseudotsuga-Tsuga forest ecosystem

    Treesearch

    Mark E. Harmon; Ken Bible; Michael G. Ryan; David C. Shaw; H. Chen; Jeffrey Klopatek; Xia Li

    2004-01-01

    Ground-based measurements of stores, growth, mortality, litterfall, respiration, and decomposition were conducted in an old-growth forest at Wind River Experimental Forest, Washington. These measurements were used to estimate: Gross (GPP) and Net Primary Production (NPP); autotrophic (Ra) and heterotrophic (Rh) respiration; and Net Ecosystem Production (NEP). Monte...

  9. Stand structure in eastside old-growth ponderosa pine forests of Oregon and northern California.

    Treesearch

    Andrew Youngblood; Timothy Max; Kent. Coe

    2004-01-01

    Quantitative metrics of horizontal and vertical structural attributes in eastside old-growth ponderosa pine (Pinus ponderosa P. and C. Lawson var. ponderosa) forests were measured to guide the design of restoration prescriptions. The age, size structure, and the spatial patterns were investigated in old-growth ponderosa pine forests at three...

  10. Old-growth forests in the Southwest and Rocky Mountain Regions - Proceedings of a workshop

    Treesearch

    Merrill R. Kaufman; W. H. Moir; Richard L. Bassett

    1992-01-01

    This paper reviews the science and management of old-growth forests and summarizes discussions among 30 participants at a workshop in Portal, Arizona, March 9-13, 1992. Concepts of old-growth forests - the perceptions, values, definitions, characteristic features, ecological functions, and landscape importance - vary widely. Because concepts are complex,...

  11. Forest carbon dynamics associated with growth and disturbances in Oklahoma and Texas, 1992-2006

    Treesearch

    Daolan Zheng; Linda S. Heath; Mark J. Ducey; James E. Smith

    2013-01-01

    Quantifying forest carbon changes associated with growth and major disturbances is important for management of greenhouse gas emissions related to forests. Regional-level approaches with improved local growth data may refine estimates obtained using coarser resolution information. This study integrates remote-sensing-derived land cover change products, harvest data,...

  12. An Old-Growth Definition for Western and Mixed Mesophytic Forests

    Treesearch

    Cathryn H. Greenberg; Donald E. McLeod; David L. Loftis

    1997-01-01

    Old growth is widely acknowledged today as an essential part of managed forests, particularly on public lands. However, this concept is relatively new, evolving since the 1970's when a grassroots movement in the Pacific Northwest began in earnest to define old growth. In response to changes in public attitude, the U.S. Department of Agriculture, Forest Service,...

  13. Spatial elements of mortality risk in old-growth forests

    USGS Publications Warehouse

    Das, Adrian; Battles, John; van Mantgem, Phillip J.; Stephenson, Nathan L.

    2008-01-01

    For many species of long-lived organisms, such as trees, survival appears to be the most critical vital rate affecting population persistence. However, methods commonly used to quantify tree death, such as relating tree mortality risk solely to diameter growth, almost certainly do not account for important spatial processes. Our goal in this study was to detect and, if present, to quantify the relevance of such processes. For this purpose, we examined purely spatial aspects of mortality for four species, Abies concolor, Abies magnifica, Calocedrus decurrens, and Pinus lambertiana, in an old-growth conifer forest in the Sierra Nevada of California, USA. The analysis was performed using data from nine fully mapped long-term monitoring plots.In three cases, the results unequivocally supported the inclusion of spatial information in models used to predict mortality. For Abies concolor, our results suggested that growth rate may not always adequately capture increased mortality risk due to competition. We also found evidence of a facilitative effect for this species, with mortality risk decreasing with proximity to conspecific neighbors. For Pinus lambertiana, mortality risk increased with density of conspecific neighbors, in keeping with a mechanism of increased pathogen or insect pressure (i.e., a Janzen-Connell type effect). Finally, we found that models estimating risk of being crushed were strongly improved by the inclusion of a simple index of spatial proximity.Not only did spatial indices improve models, those improvements were relevant for mortality prediction. For P. lambertiana, spatial factors were important for estimation of mortality risk regardless of growth rate. For A. concolor, although most of the population fell within spatial conditions in which mortality risk was well described by growth, trees that died occurred outside those conditions in a disproportionate fashion. Furthermore, as stands of A. concolor become increasingly dense, such spatial

  14. Topography and traits modulate drought effects on tree growth in a tropical second-growth forest

    NASA Astrophysics Data System (ADS)

    Schwartz, N.; Uriarte, M.; Feng, X.; Quebbeman, A.

    2016-12-01

    Changes in the frequency and severity of drought will affect tropical forests via changes in tree growth and mortality, carbon dynamics, and community composition. However, predicting drought responses is challenging because individual trees experience drought differently due to local variation in water availability associated with soil type, fine scale topographic variation, and competition for water. Furthermore, differences in physiology and functional traits affect species responses to drought. These differences underlie observed variation in drought response, yet few studies have investigated the relationship between fine-scale topography, neighborhood crowding, functional traits, and drought impacts. In this study, we aimed to understand: how does drought affect tree growth, and does this effect change with topography and neighborhood crowding? Furthermore, how do functional traits modulate the effect of drought and its interaction with topography and crowding? To address these questions, we developed a hierarchical Bayesian model that quantified the effects of drought and topography (slope and curvature) on individual tree growth, and the way these effects are modulated by two key traits related to water use: specific leaf area (SLA) and wood density (WD). We fit this model with spatially explicit annual census data, spanning one drought year and one non-drought year, from five second-growth forest plots in Puerto Rico, along with 1 m resolution topography data. We found variable drought response across species, with species with higher WD and lower SLA showing stronger reductions of growth during drought. The effects of slope and curvature also varied across species, with growth of species with lower WD more negatively associated with slope and positively associated with curvature. Contrary to expectations, drought response did not vary strongly with topography. Crowding negatively affected growth for most species, and this effect was amplified during

  15. Mapping forest structure, species gradients and growth in an urban area using lidar and hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Gu, Huan

    Urban forests play an important role in the urban ecosystem by providing a range of ecosystem services. Characterization of forest structure, species variation and growth in urban forests is critical for understanding the status, function and process of urban ecosystems, and helping maximize the benefits of urban ecosystems through management. The development of methods and applications to quantify urban forests using remote sensing data has lagged the study of natural forests due to the heterogeneity and complexity of urban ecosystems. In this dissertation, I quantify and map forest structure, species gradients and forest growth in an urban area using discrete-return lidar, airborne imaging spectroscopy and thermal infrared data. Specific objectives are: (1) to demonstrate the utility of leaf-off lidar originally collected for topographic mapping to characterize and map forest structure and associated uncertainties, including aboveground biomass, basal area, diameter, height and crown size; (2) to map species gradients using forest structural variables estimated from lidar and foliar functional traits, vegetation indices derived from AVIRIS hyperspectral imagery in conjunction with field-measured species data; and (3) to identify factors related to relative growth rates in aboveground biomass in the urban forests, and assess forest growth patterns across areas with varying degree of human interactions. The findings from this dissertation are: (1) leaf-off lidar originally acquired for topographic mapping provides a robust, potentially low-cost approach to quantify spatial patterns of forest structure and carbon stock in urban areas; (2) foliar functional traits and vegetation indices from hyperspectral data capture gradients of species distributions in the heterogeneous urban landscape; (3) species gradients, stand structure, foliar functional traits and temperature are strongly related to forest growth in the urban forests; and (4) high uncertainties in our

  16. Evaluating models of climate and forest vegetation

    NASA Technical Reports Server (NTRS)

    Clark, James S.

    1992-01-01

    Understanding how the biosphere may respond to increasing trace gas concentrations in the atmosphere requires models that contain vegetation responses to regional climate. Most of the processes ecologists study in forests, including trophic interactions, nutrient cycling, and disturbance regimes, and vital components of the world economy, such as forest products and agriculture, will be influenced in potentially unexpected ways by changing climate. These vegetation changes affect climate in the following ways: changing C, N, and S pools; trace gases; albedo; and water balance. The complexity of the indirect interactions among variables that depend on climate, together with the range of different space/time scales that best describe these processes, make the problems of modeling and prediction enormously difficult. These problems of predicting vegetation response to climate warming and potential ways of testing model predictions are the subjects of this chapter.

  17. Gender-related distributions of Fraxinus mandshurica in secondary and old-growth forests

    NASA Astrophysics Data System (ADS)

    Zhang, Chunyu; Zhao, Xiuhai; Gao, Lushuang; Gadow, Klaus von

    2010-01-01

    This study presents new findings about gender-related spatial distributions of the strictly dioecious tree species Fraxinus mandshurica. The observations were collected in three large field plots in secondary and old-growth forests in northeastern China, covering the 4-year period from 2005 to 2008. Tree diameters were not significantly different between genders in the young secondary forests. In the old-growth forest, however, the diameters of male trees were significantly greater than those of female trees. The sex ratio did not significantly deviate from 1:1 in the secondary forests, but was male-biased in the old-growth forest. Spatial segregation between genders was found in the secondary forests, but male and female trees were spatially independent in the old-growth forest. This research complements the current knowledge about sex ratios in secondary and old-growth forests, and about spatial patterns and intra- and intersexual interactions of the dioecious species, F. mandshurica. The available evidence suggests that male and female individuals show a different response to specific microenvironments in the three forest successional stages, which suggests that there are differences in resource requirements between genders.

  18. Spider (Arachnida, Araneae) diversity in secondary and old-growth southern Atlantic forests of Paraná state, Brazil.

    PubMed

    Raub, Florian; Höfer, Hubert; Scheuermann, Ludger

    2017-07-01

    The data presented here have been collected in the southern part of the Atlantic Forest (Mata Atlântica) in the state of Paraná, Brazil within a bilateral scientific project (SOLOBIOMA). The project aimed to assess the quality of secondary forests of different regeneration stages in comparison with old-growth forests with regard to diversity of soil animals and related functions. The Atlantic Forest is a hotspot of biological diversity with an exceptionally high degree of endemic species, extending over a range of 3,500 km along the coast of Brazil. The anthropogenic pressure in the region is very high with three of the biggest cities of Brazil (São Paulo, Rio de Janeiro, and Curitiba) lying in its extension. An evaluation of the value of secondary forests for biodiversity conservation is becoming more and more important due to the complete disappearance of primary forests. In 2005, we sampled spiders in 12 sites of three successional stages (5-8, 10-15, 35-50 yr old, three replicates of each forest stage) and old-growth forests (> 100 yr untouched, also three replicates). All sites were inside a private nature reserve (Rio Cachoeira Nature Reserve). We repeated the sampling design and procedure in 2007 in a second private reserve (Itaqui Nature Reserve). The two nature reserves are within about 25 km of each other within a well preserved region of the Mata Atlântica, where the matrix of the landscape mosaic is still forest. A widely accepted standard protocol was used in a replicated sampling design to apply statistical analyses to the resulting data set and allow for comparison with other studies in Brazil. Spiders were sorted to family level and counted; the adult spiders further identified to species if possible or classified as morphospecies with the help of several spider specialists. © 2017 by the Ecological Society of America.

  19. Assessing the effects of management on forest growth across France: insights from a new functional–structural model

    PubMed Central

    Guillemot, Joannès; Delpierre, Nicolas; Vallet, Patrick; François, Christophe; Martin-StPaul, Nicolas K.; Soudani, Kamel; Nicolas, Manuel; Badeau, Vincent; Dufrêne, Eric

    2014-01-01

    Background and Aims The structure of a forest stand, i.e. the distribution of tree size features, has strong effects on its functioning. The management of the structure is therefore an important tool in mitigating the impact of predicted changes in climate on forests, especially with respect to drought. Here, a new functional–structural model is presented and is used to assess the effects of management on forest functioning at a national scale. Methods The stand process-based model (PBM) Castanea was coupled to a stand structure module (SSM) based on empirical tree-to-tree competition rules. The calibration of the SSM was based on a thorough analysis of intersite and interannual variability of competition asymmetry. The coupled Castanea–SSM model was evaluated across France using forest inventory data, and used to compare the effect of contrasted silvicultural practices on simulated stand carbon fluxes and growth. Key Results The asymmetry of competition varied consistently with stand productivity at both spatial and temporal scales. The modelling of the competition rules enabled efficient prediction of changes in stand structure within the Castanea PBM. The coupled model predicted an increase in net primary productivity (NPP) with management intensity, resulting in higher growth. This positive effect of management was found to vary at a national scale across France: the highest increases in NPP were attained in forests facing moderate to high water stress; however, the absolute effect of management on simulated stand growth remained moderate to low because stand thinning involved changes in carbon allocation at the tree scale. Conclusions This modelling approach helps to identify the areas where management efforts should be concentrated in order to mitigate near-future drought impact on national forest productivity. Around a quarter of the French temperate oak and beech forests are currently in zones of high vulnerability, where management could thus mitigate

  20. Old-growth definition for evergreen bay forests and related seral communities. Forest Service general technical report

    SciTech Connect

    McKevlin, M.R.

    1996-09-01

    This document describes old-growth conditions in an evergreen bay forest stand. Bay forests occur throughout the Atlantic and Gulf Coastal Plains. However, they are considered rare and are present across the landscape in a patchwork mosaic with other forest types in various stages of succession. Bay forests can be found associated with pocosins. Carolina bays and sandhill seeps, stream heads, and stream margins. The dominant species include loblolly-bay, sweetbay, and redbay, hence the name evergreen bay forest. However, several other swamp species associates are common, as well as many highly flammable shrub species. This forest type is subject to infrequent, high intensity, widespread disturbances such as fire. Fire is necessary to the nutrient cycling of this forest type and in conjunction with hydrology, controls succession. These stands are frequently inundated by surface water, resulting in the development of histic soils low in fertility. Alteration of the hydrology by man and catastrophic wildfire are considered to be the greatest threats to the existence of bay forests.

  1. Northwest Forest Plan—the first 10 years (1994-2003): status and trend of late-successional and old-growth forest.

    Treesearch

    Melinda Moeur; Thomas A. Spies; Miles Hemstrom; Jon R. Martin; James Alegria; Julie Browning; John Cissel; Warren B. Cohen; Thomas E. Demeo; Sean Healey; Ralph. Warbington

    2005-01-01

    We monitored the status and trend of late-successional and old-growth forest (older forest) on 24 million ac of land managed by the Forest Service, Bureau of Land Management, and National Park Service in the Northwest Forest Plan (the Plan) area between 1994 and 2003. We developed baseline maps from satellite imagery of older forest conditions at the start of the Plan...

  2. An Old-Growth Definition for Western Hardwood Gallery Forests

    Treesearch

    Kelly Kindscher; Jenny Holah

    1998-01-01

    Western hardwood gallery forests are found across an extremely large, diverse geographical area that encompasses the Great Plains in the United States and Canada. Remnant forests of this type still exist in the "Prairie Peninsula," which historically projected an eastern finger into Ohio. The forests are restricted to floodplains of major rivers and are in...

  3. Longleaf pine forests and woodlands: old growth under fire!

    Treesearch

    Joan L. Walker

    1999-01-01

    The author discusses a once widespread forest type of the Southeast – longleaf pine dominated forests and woodlands. This system depends on fire – more or less frequent, and often of low intensity. Because human-mediated landscape fragmentation has drastically changed the behavior of fire on longleaf pine dominated landscapes, these forests and woodlands will never be...

  4. Influence of competition and age on tree growth in structurally complex old-growth forests in northern Minnesota, USA

    Treesearch

    Tuomas Aakala; Shawn Fraver; Anthony W. D' Amato; Brian J. Palik

    2013-01-01

    Factors influencing tree growth in structurally complex forests remain poorly understood. Here we assessed the influence of competition on Pinus resinosa (n = 224) and Pinus strobus (n = 90) growth in four old-growth stands in Minnesota, using mixed effects models. A subset of trees, with...

  5. Liana infestation impacts tree growth in a lowland tropical moist forest

    NASA Astrophysics Data System (ADS)

    van der Heijden, G. M. F.; Phillips, O. L.

    2009-10-01

    Ecosystem-level estimates of the effect of lianas on tree growth in mature tropical forests are needed to evaluate the functional impact of lianas and their potential to affect the ability of tropical forests to sequester carbon, but these are currently lacking. Using data collected on tree growth rates, local growing conditions and liana competition in five permanent sampling plots in Amazonian Peru, we present the first ecosystem-level estimates of the effect of lianas on above-ground productivity of trees. By first constructing a multi-level linear mixed effect model to predict individual-tree diameter growth model using individual-tree growth conditions, we were able to then estimate stand-level above-ground biomass (AGB) increment in the absence of lianas. We show that lianas, mainly by competing above-ground with trees, reduce tree annual above-ground stand-level biomass increment by ~10%, equivalent to 0.51 Mg dry weight ha-1 yr-1 or 0.25 Mg C ha-1 yr-1. AGB increment of lianas themselves was estimated to be 0.15 Mg dry weight ha-1 yr-1 or 0.07 Mg C ha-1 yr-1, thus only compensating ~29% of the liana-induced reduction in ecosystem AGB increment. Increasing liana pressure on tropical forests will therefore not only tend to reduce their carbon storage capacity, by indirectly promoting tree species with low-density wood, but also their rate of carbon uptake, with potential consequences for the rate of increase in atmospheric carbon dioxide.

  6. Liana infestation impacts tree growth in a lowland tropical moist forest

    NASA Astrophysics Data System (ADS)

    van der Heijden, G. M. F.; Phillips, O. L.

    2009-03-01

    Stand-level estimates of the effect of lianas on tree growth in mature tropical forests are needed to evaluate the functional impact of lianas and their potential to affect the ability of tropical forests to sequester carbon, but these are currently lacking. Using data collected on tree growth rates, local growing conditions and liana competition in five permanent sampling plots in Amazonian Peru, we present the first such estimates of the effect of lianas on above-ground productivity of trees. By constructing a multi-level linear mixed effect model to predict individual tree diameter growth model using individual tree growth conditions, we were able to estimate stand-level above-ground biomass (AGB) increment in the absence of lianas. We show that lianas, mainly by competing above-ground with trees, reduce tree annual above-ground stand-level biomass by ~10%, equivalent to 0.51 Mg dry weight ha-1 yr-1 or 0.25 Mg C ha-1 yr-1. AGB increment of lianas themselves was estimated to be 0.15 Mg dry weight ha-1 yr-1 or 0.07 Mg C ha-1 yr-1, thus only compensating ~29% of the liana-induced reduction in stand-level AGB increment. Increasing liana pressure on tropical forests may therefore not only reduce their carbon storage capacity, by indirectly promoting tree species with low-density wood, but also their rate of carbon uptake, with potential consequences for the rate of increase in atmospheric carbon dioxide.

  7. Old-growth forests in the Sierra Nevada: by type in 1945 and 1993 and ownership in 1993.

    Treesearch

    Debby Beardsley; Charles Bolsinger; Ralph. Warbington

    1999-01-01

    This report presents estimates of old-growth forest area in the Sierra Nevada by forest type in 1993 and 1945 and by old-growth stand characteristics as they existed in 1993. Ecological old-growth definitions for each forest type are used.

  8. Evaluating Heterogeneous Conservation Effects of Forest Protection in Indonesia

    PubMed Central

    Shah, Payal; Baylis, Kathy

    2015-01-01

    Establishing legal protection for forest areas is the most common policy used to limit forest loss. This article evaluates the effectiveness of seven Indonesian forest protected areas introduced between 1999 and 2012. Specifically, we explore how the effectiveness of these parks varies over space. Protected areas have mixed success in preserving forest, and it is important for conservationists to understand where they work and where they do not. Observed differences in the estimated treatment effect of protection may be driven by several factors. Indonesia is particularly diverse, with the landscape, forest and forest threats varying greatly from region to region, and this diversity may drive differences in the effectiveness of protected areas in conserving forest. However, the observed variation may also be spurious and arise from differing degrees of bias in the estimated treatment effect over space. In this paper, we use a difference-in-differences approach comparing treated observations and matched controls to estimate the effect of each protected area. We then distinguish the true variation in protected area effectiveness from spurious variation driven by several sources of estimation bias. Based on our most flexible method that allows the data generating process to vary across space, we find that the national average effect of protection preserves an additional 1.1% of forest cover; however the effect of individual parks range from a decrease of 3.4% to an increase of 5.3% and the effect of most parks differ from the national average. Potential biases may affect estimates in two parks, but results consistently show Sebangau National Park is more effective while two parks are substantially less able to protect forest cover than the national average. PMID:26039754

  9. Evaluating heterogeneous conservation effects of forest protection in Indonesia.

    PubMed

    Shah, Payal; Baylis, Kathy

    2015-01-01

    Establishing legal protection for forest areas is the most common policy used to limit forest loss. This article evaluates the effectiveness of seven Indonesian forest protected areas introduced between 1999 and 2012. Specifically, we explore how the effectiveness of these parks varies over space. Protected areas have mixed success in preserving forest, and it is important for conservationists to understand where they work and where they do not. Observed differences in the estimated treatment effect of protection may be driven by several factors. Indonesia is particularly diverse, with the landscape, forest and forest threats varying greatly from region to region, and this diversity may drive differences in the effectiveness of protected areas in conserving forest. However, the observed variation may also be spurious and arise from differing degrees of bias in the estimated treatment effect over space. In this paper, we use a difference-in-differences approach comparing treated observations and matched controls to estimate the effect of each protected area. We then distinguish the true variation in protected area effectiveness from spurious variation driven by several sources of estimation bias. Based on our most flexible method that allows the data generating process to vary across space, we find that the national average effect of protection preserves an additional 1.1% of forest cover; however the effect of individual parks range from a decrease of 3.4% to an increase of 5.3% and the effect of most parks differ from the national average. Potential biases may affect estimates in two parks, but results consistently show Sebangau National Park is more effective while two parks are substantially less able to protect forest cover than the national average.

  10. Spatial aspects of tree mortality strongly differ between young and old-growth forests.

    PubMed

    Larson, Andrew J; Lutz, James A; Donato, Daniel C; Freund, James A; Swanson, Mark E; HilleRisLambers, Janneke; Sprugel, Douglas G; Franklin, Jerry F

    2015-11-01

    Rates and spatial patterns of tree mortality are predicted to change during forest structural development. In young forests, mortality should be primarily density dependent due to competition for light, leading to an increasingly spatially uniform pattern of surviving trees. In contrast, mortality in old-growth forests should be primarily caused by contagious and spatially autocorrelated agents (e.g., insects, wind), causing spatial aggregation of surviving trees to increase through time. We tested these predictions by contrasting a three-decade record of tree mortality from replicated mapped permanent plots located in young (< 60-year-old) and old-growth (> 300-year-old) Abies amabilis forests. Trees in young forests died at a rate of 4.42% per year, whereas trees in old-growth forests died at 0.60% per year. Tree mortality in young forests was significantly aggregated, strongly density dependent, and caused live tree patterns to become more uniform through time. Mortality in old-growth forests was spatially aggregated, but was density independent and did not change the spatial pattern of surviving trees. These results extend current theory by demonstrating that density-dependent competitive mortality leading to increasingly uniform tree spacing in young forests ultimately transitions late in succession to a more diverse tree mortality regime that maintains spatial heterogeneity through time.

  11. Nutrient foraging strategies are associated with productivity and population growth in forest shrubs.

    PubMed

    Caplan, Joshua S; Stone, Bram W G; Faillace, Cara A; Lafond, Jonathan J; Baumgarten, Joni M; Mozdzer, Thomas J; Dighton, John; Meiners, Scott J; Grabosky, Jason C; Ehrenfeld, Joan G

    2017-04-01

    Temperate deciduous forest understoreys are experiencing widespread changes in community composition, concurrent with increases in rates of nitrogen supply. These shifts in plant abundance may be driven by interspecific differences in nutrient foraging (i.e. conservative vs. acquisitive strategies) and, thus, adaptation to contemporary nutrient loading conditions. This study sought to determine if interspecific differences in nutrient foraging could help explain patterns of shrub success and decline in eastern North American forests. Using plants grown in a common garden, fine root traits associated with nutrient foraging were measured for six shrub species. Traits included the mean and skewness of the root diameter distribution, specific root length (SRL), C:N ratio, root tissue density, arbuscular mycorrhizal colonization and foraging precision. Above- and below-ground productivity were also determined for the same plants, and population growth rates were estimated using data from a long-term study of community dynamics. Root traits were compared among species and associations among root traits, measures of productivity and rates of population growth were evaluated. Species fell into groups having thick or thin root forms, which correspond to conservative vs. acquisitive nutrient foraging strategies. Interspecific variation in root morphology and tissue construction correlated with measures of productivity and rates of cover expansion. Of the four species with acquisitive traits, three were introduced species that have become invasive in recent decades, and the fourth was a weedy native. In contrast, the two species with conservative traits were historically dominant shrubs that have declined in abundance in eastern North American forests. In forest understoreys of eastern North America, elevated nutrient availability may impose a filter on species success in addition to above-ground processes such as herbivory and overstorey canopy conditions. Shrubs that have

  12. Plant hydraulic traits govern forest water use and growth

    NASA Astrophysics Data System (ADS)

    Matheny, Ashley; Bohrer, Gil; Fiorella, Rich; Mirfenderesgi, Golnazalsadat

    2016-04-01

    species, like red maple. Advanced plant hydrodynamic models, including the FETCH2 model, are able to capture the effects that traits regulating water loss (e. g. isohydry/anisohydry, conductivity of woody tissue, and rooting depth) impose upon transpiration at scales of a single tree to a whole forest. The integration of detailed knowledge of species-specific hydraulic traits, available through the TRY Global Plant Trait Database, provides biologically relevant constraints for the governing parameters within these modeling systems. By incorporating the effects of plant hydraulic traits at the leaf, stem, and root levels, with mechanistically based predictions of transpiration, growth, and mortality, we can improve simulations of the surface energy budget and global carbon and water balances.

  13. Status of mature and old-growth forests in the Pacific Northwest.

    PubMed

    Strittholt, James R; DellaSala, Dominick A; Jiang, Hong

    2006-04-01

    Nearly 10 million ha of federal lands in the Pacific Northwest have been managed under the Northwest Forest Plan since 1994. The plan reduced logging levels by 80%; only recently, however have inventories on status and condition of mature and old-growth forests become available. Our objectives were to (1) determine the areal extent of old (> 150 years) and mature (50-150 years) conifer forests based on 2000 Landsat 7 ETM+ imagery, (2) examine levels of protection, (3) determine the degree of additional protection afforded to old and mature conifer forests if late-successional reserves (LSRs) and inventoried roadless areas (IRAs) were fully protected, and (4) review management options to achieve greater protection of older forests. The historical extent of old-growth forest in the Pacific Northwest was roughly two-thirds (16,672,976 ha) of the total land area. Since the time of European settlement, approximately 72% of the original old-growth conifer forest has been lost, largely through logging and other developments. Of the remaining old growth, the Central and Southern Cascades and Klamath-Siskiyou account for nearly half Mature conifer area (4,758,596 ha) nearly equaled the amount of old conifer More than 78% of the old growth and 50% of mature forest were located on public lands. Approximately one-quarter (1,201,622 ha) of the old-growth conifer (or 7% of the historical old-growth area) was classified as GAP status 1 (strictly protected) or GAP status 2 (moderately protected). The total area of LSRs was slightly more than 3 million ha, approximately 36% (1,073,299 ha) of which contained old-growth conifer forest. Combined old and mature conifer within LSRs was approximately 59% of the total LSR area. The total amount of IRA for the Pacific Northwest was approximately 1,563,370 ha; of this, 526,912 ha (34%) was old growth. The combined area of old-growth conifer forest accounted for by protected areas (GAP 1 and 2), LSRs, and IRAs was 2,401,780 ha, which

  14. Tree growth and recruitment in a leveed floodplain forest in the Mississippi River Alluvial Valley, USA

    USGS Publications Warehouse

    Gee, Hugo K.W.; King, Sammy L.; Keim, Richard F.

    2014-01-01

    Flooding is a defining disturbance in floodplain forests affecting seed germination, seedling establishment, and tree growth. Globally, flood control, including artificial levees, dams, and channelization has altered flood regimes in floodplains. However, a paucity of data are available in regards to the long-term effects of levees on stand establishment and tree growth in floodplain forests. In this study, we used dendrochronological techniques to reconstruct tree recruitment and tree growth over a 90-year period at three stands within a ring levee in the Mississippi River Alluvial Valley (MAV) and to evaluate whether recruitment patterns and tree growth changed following levee construction. We hypothesized that: (1) sugarberry is increasing in dominance and overcup oak (Quercus lyrata) is becoming less dominant since the levee, and that changes in hydrology are playing a greater role than canopy disturbance in these changes in species dominance; and (2) that overcup oak growth has declined following construction of the levee and cessation of overbank flooding whereas that of sugarberry has increased. Recruitment patterns shifted from flood-tolerant overcup oak to flood-intolerant sugarberry (Celtis laevigata) after levee construction. None of the 122 sugarberry trees cored in this study established prior to the levee, but it was the most common species established after the levee. The mechanisms behind the compositional change are unknown, however, the cosmopolitan distribution of overcup oak during the pre-levee period and sugarberry during the post-levee period, the lack of sugarberry establishment in the pre-levee period, and the confinement of overcup oak regeneration to the lowest areas in each stand after harvest in the post-levee period indicate that species-specific responses to flooding and light availability are forcing recruitment patterns. Overcup oak growth was also affected by levee construction, but in contrast to our hypothesis, growth actually

  15. Evaluating growth performance of young stands

    Treesearch

    A. L. Roe; R. E. Benson

    1966-01-01

    A simple procedure for evaluating the diameter growth of young stands in relation to potential growth is described. A comparison technique is developed which contrasts relative diameter of crop trees to the relative diameter growth of the last decade to show the condition and trend of growth in the stand. The method is objective, easy to use, and has several...

  16. Changes in conifer and deciduous forest foliar and forest floor chemistry and basal area tree growth across a nitrogen (N) deposition gradient in the northeastern US.

    PubMed

    Boggs, Johnny L; McNulty, Steven G; Pardo, Linda H

    2007-10-01

    We evaluated foliar and forest floor chemistry across a gradient of N deposition in the Northeast at 11 red spruce (Picea rubens Sarg.) sites in 1987/1988 and foliar and forest floor chemistry and basal area growth at six paired spruce and deciduous sites in 1999. The six red spruce plots were a subset of the original 1987/1988 spruce sites. In 1999, we observed a significant correlation between mean growing season temperature and red spruce basal area growth. Red spruce and deciduous foliar %N correlated significantly with N deposition. Although N deposition has not changed significantly from 1987/1988 to 1999, net nitrification potential decreased significantly at Whiteface. This decrease in net potential nitrification is not consistent with the N saturation hypothesis and suggests that non-N deposition controls, such as climatic factors and immobilization of down dead wood, might have limited N cycling.

  17. Analysis of growth trend changes for 51 temperate tree species using Korea national forest inventory data

    NASA Astrophysics Data System (ADS)

    Park, M.; Moon, M.; Park, J.; Cho, S.; Kim, H. S.

    2016-12-01

    Individual tree growth rates can be affected by various factors such as species, soil fertility, stand development stage, disturbance, and climate etc. To estimate the effect of changes in tree growth rate on the structure and functionality of forest ecosystem in the future, we analyzed the change of species-specific growth trends using the fifth Korea national forest inventory data, which was collected from 2006 to 2010. The ring samples of average tree were collected from nationwide inventory plots and the total number of individual tree ring series was 69,128 covering 185 tree species. Among those, fifty one species with more than 100 tree ring series were used for our analysis. For growth-trend analysis, standardized regional curves of individual species growth were generated from three forest zone in South Korea; subarctic, cool temperate, warm temperate forest zone. Then individual tree ring series was indexed by dividing the growth of the tree by expected growth from standardized regional curves. Then the ratio of all tree ring series were aligned by year and the Spearman's correlation coefficient of each species was calculated. The results show that most of species had increasing growth rates as forests developed after Korean war. For the last thirty years, 67.3% of species including Quercus spp. and Zelkova serrata had positive growth trends, on the other hand, 11.5% of species including Pinus spp. showed negative growth trends probably due to the changes in successional stages in Korean forests and climate change. These trends also vary with climate zone and species. For examples, Pinus densiflora, which showed negative growth trend overall, had steep negative growth trends in boreal and temperate zone, whereas it showed no specific trend in sub-tropical climate zone. Our trend analysis on 51 temperate tree species growth will be essential to predict the temperate forests species change for the this century.

  18. Gap Dynamics and Structure of Two Old-Growth Beech Forest Remnants in Slovenia

    PubMed Central

    Rugani, Tihomir; Diaci, Jurij; Hladnik, David

    2013-01-01

    Context Due to a long history of intensive forest exploitation, few European beech (Fagus sylvatica L.) old-growth forests have been preserved in Europe. Material and Methods We studied two beech forest reserves in southern Slovenia. We examined the structural characteristics of the two forest reserves based on data from sample plots and complete inventory obtained from four previous forest management plans. To gain a better understanding of disturbance dynamics, we used aerial imagery to study the characteristics of canopy gaps over an 11-year period in the Kopa forest reserve and a 20-year period in the Gorjanci forest reserve. Results The results suggest that these forests are structurally heterogeneous over small spatial scales. Gap size analysis showed that gaps smaller than 500 m2 are the dominant driving force of stand development. The percentage of forest area in canopy gaps ranged from 3.2 to 4.5% in the Kopa forest reserve and from 9.1 to 10.6% in the Gorjanci forest reserve. These forests exhibit relatively high annual rates of coverage by newly established (0.15 and 0.25%) and closed (0.08 and 0.16%) canopy gaps. New gap formation is dependant on senescent trees located throughout the reserve. Conclusion We conclude that these stands are not even-sized, but rather unevenly structured. This is due to the fact that the disturbance regime is characterized by low intensity, small-scale disturbances. PMID:23308115

  19. Multidecadal analysis of forest growth and albedo in boreal Finland

    NASA Astrophysics Data System (ADS)

    Lukeš, Petr; Stenberg, Pauline; Mõttus, Matti; Manninen, Terhikki; Rautiainen, Miina

    2016-10-01

    It is well known that forests serve as carbon sinks. However, the balancing effect of afforestation and increased forest density on global warming due to carbon storage may be lost by low albedo (thus high absorption) of the forests. In the last 30 years, there has been a steady increase in the growing stock of Finnish forests by nearly a quarter while the area of the forests has remained virtually unchanged. Such increase in forest density together with the availability of detailed forest inventories provided by the Multi-Source National Forest Inventory (MS-NFI) in high spatial resolution makes Finland an ideal candidate for exploring the effects of increased forest density on satellite derived estimates of bio-geochemical products e.g. albedo (directional-hemispherical reflectance, DHR), fraction of photosynthetically active radiation absorbed by canopies (fAPAR), leaf area index (LAI) and normalized difference vegetation index (NDVI) in both current and long-term perspective. In this study, we first used MODIS-based vegetation satellite products for Finnish forests to study their seasonal patterns and interrelations. Next, the peak growing season observations are linked to the MS-NFI database to yield the generic relationships between forest density and the satellite-derived vegetation indicators. Finally, long-term GIMMS3g datasets between 1982 and 2011 (2008 for DHR) are analyzed and interpreted using forest inventory data. The vegetation peak growing season NIR DHR and VIS DHR showed weak to moderate negative correlation with fAPAR, whereas there was no correlation between NIR DHR and fAPAR. Next, we show that the spectral albedos in the near-infrared region (NIR DHR) showed weak negative correlation with forest biomass, basal area or canopy cover whereas, as expected, the spectral albedo in the visible region (VIS DHR) correlated negatively with these measures of forest density. Interestingly, the increase in forest density (biomass per ha) of Finnish

  20. Vegetation structure determination using LIDAR data and the forest growth parameters

    NASA Astrophysics Data System (ADS)

    Rybansky, M.; Brenova, M.; Cermak, J.; van Genderen, J.; Sivertun, Å.

    2016-06-01

    The goal of this paper is to identify the main vegetation factors in the terrain, which are important for the analysis of forest structure. Such an analysis is important for forestry, rescue operations management during crises situations and disasters such as fires, storms, earthquakes and military analysis (transportation, cover, concealment, etc.). For the forest structure determination, both LIDAR and the forest growth prediction analysis were used. As main results, the vegetation height, tree spacing and stem diameters were determined

  1. Increased water use efficiency but contrasting tree growth patterns in Fitzroya cupressoides forests of southern Chile during recent decades

    NASA Astrophysics Data System (ADS)

    Urrutia-Jalabert, Rocío.; Malhi, Yadvinder; Barichivich, Jonathan; Lara, Antonio; Delgado-Huertas, Antonio; Rodríguez, Carmen Gloria; Cuq, Emilio

    2015-12-01

    Little is known about how old-growth and massive forests are responding to environmental change. We investigated tree-ring growth and carbon isotopes of the long-lived and high biomass Fitzroya cupressoides in two stands growing in contrasting environmental conditions in the Coastal Range (~300 years old) and Andean Cordilleras (>1500 years old) of southern Chile. The interannual variability in δ13C was assessed for the period 1800-2010, and changes in discrimination and intrinsic water use efficiency (iWUE) were evaluated in relation to changes in climate and tree-ring growth during the last century. 13C discrimination has significantly decreased, and iWUE has increased since the 1900s in both sites. However, these trends in isotopic composition have been accompanied by different growth patterns: decreasing growth rates in the Coastal Range since the 1970s and increasing growth rates in the Andes since the 1900s. Trees growing in the Coastal Range have become more efficient in their use of water, probably due to reduced stomatal conductance caused by increases in CO2 and warming. Trees growing in the Andes have also become more water use efficient, but this has been likely due to increased photosynthetic rates. Fitzroya forests, including particularly old-growth stands, are responding to recent environmental changes, and their response has been site dependent. The growth of forests under a more Mediterranean climate influence and restrictive soil conditions in the Coastal Range has been more negatively affected by current warming and drying; while the growth of old stands in the wet Andes has been positively affected by changes in climate (decreasing cloudiness) and increasing CO2. Permanent monitoring of these endangered forests under ongoing environmental changes is needed in order to reassure the long-term preservation of this millennial-aged species.

  2. Growth and ecophysiological acclimation of the foliose lichen Lobaria pulmonaria in forests with contrasting light climates.

    PubMed

    Gauslaa, Yngvar; Lie, Marit; Solhaug, Knut Asbjørn; Ohlson, Mikael

    2006-03-01

    This study aims to assess biomass and area growth of 600 thalli of the old forest lichen, Lobaria pulmonaria, transplanted to three successional boreal forest stands with (1) natural rainfall regime, (2) additional moistening during dry days, and (3) additional moistening with added nutrients. Mean biomass growth during 100 days varied from 8.3% in the dark young spruce forest to 23.1% in the clear-cut area, with the old forest in between (16.0%). Additional moistening did not enhance lichen growth, probably because the transplantation period was wet. Nutrient additions slightly increased area growth compared to artificial water additions only. Growth was determined by a combination of external (forest stand, site factors) and internal factors (chlorophyll content, biomass per area). Transplants acclimated to high light by increasing thickness and chlorophyll a/b-ratio. Some visible bleaching and a strong positive correlation between chlorophyll content per area and lichen growth in clear-cuts suggest some high light-induced chlorophyll degradation. We believe that biomass growth and natural occurrence of L. pulmonaria is controlled by a delicate balance between light availability and desiccation risk, and that the species is confined to old forests due to a physiological trade-off between growth potential and fatal desiccation damage, both of which increase with increasing light. The discrepancy between potential and realized ecological niches is probably caused by a long-term risk to be killed in open habitats by high light during long periods with no rain.

  3. Remnant trees affect species composition but not structure of tropical second-growth forest.

    PubMed

    Sandor, Manette E; Chazdon, Robin L

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2-3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests ("control plots"). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields.

  4. Remnant Trees Affect Species Composition but Not Structure of Tropical Second-Growth Forest

    PubMed Central

    Sandor, Manette E.; Chazdon, Robin L.

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2–3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests (“control plots”). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields. PMID:24454700

  5. [Forest ecosystem service and its evaluation in China].

    PubMed

    Fang, Jin; Lu, Shaowei; Yu, Xinxiao; Rao, Liangyi; Niu, Jianzhi; Xie, Yuanyuan; Zhag, Zhenming

    2005-08-01

    Facing the relative lag of forest ecosystem service and estimation in China, this paper proposed to quickly carry out the research on the evaluation of forest ecosystem service. On the basis of the classification of forest ecosystem types in China, the service of artificial and semi-artificial forest ecosystems was investigated, which was divided into eight types, i.e., timber and other products, recreation and eco-tourism, water storage, C fixation and O2 release, nutrient cycling, air quality purifying, erosion control, and habitat provision. According to the assessment index system for global ecosystem service proposed by Costanza et al., a series of assessment index system suitable for Chinese forest ecosystem service was set up, by which, the total value of forest ecosystem service in China was estimated to be 30 601.20 x 10(8) yuan x yr(-1), including direct and indirect economic value about 1 920.23 x 10(8) and 28 680.97 x 10(8) yuan x yr(-1), respectively. The indirect value was as 14.94 times as the direct one. The research aimed to bring natural resources and environment factors into the account system of national economy quickly, and to realize the green GDP at last, which would be helpful to realize sustainable development and environment protection.

  6. Forests

    Treesearch

    Louis R. Iverson; Mark W. Schwartz

    1994-01-01

    Originally diminished by development, forests are coming back: forest biomass is accumulating. Forests are repositories for many threatened species. Even with increased standing timber, however, biodiversity is threatened by increased forest fragmentation and by exotic species.

  7. Accuracy and equivalence testing of crown ratio models and assessment of their impact on diameter growth and basal area increment predictions of two variants of the Forest Vegetation Simulator

    Treesearch

    Laura P. Leites; Andrew P. Robinson; Nicholas L. Crookston

    2009-01-01

    Diameter growth (DG) equations in many existing forest growth and yield models use tree crown ratio (CR) as a predictor variable. Where CR is not measured, it is estimated from other measured variables. We evaluated CR estimation accuracy for the models in two Forest Vegetation Simulator variants: the exponential and the logistic CR models used in the North...

  8. Some estimates of growth and mortality from the Malheur National Forest in eastern Oregon.

    Treesearch

    Donald R. Gedney; Floyd A. Johnson; Vernon E. Hicks

    1959-01-01

    During 1955-56 an inventory was made of forested land in the Middle Fork Working Circle of the Malheur National Forest to provide information necessary for calculation of the allowable cut and for other management purposes. The growth and mortality estimates in the following report were obtained from this inventory. Although the estimates apply directly to the Middle...

  9. Foliar and ecosystem respiration in an old-growth tropical rain forest

    Treesearch

    Molly A. Cavaleri; Steven F. Oberbauer; Michael G. Ryan

    2008-01-01

    Foliar respiration is a major component of ecosystem respiration, yet extrapolations are often uncertain in tropical forests because of indirect estimates of leaf area index (LAI).A portable tower was used to directly measure LAI and night-time foliar respiration from 52 vertical transects throughout an old-growth tropical rain forest in Costa Rica. In this study, we (...

  10. Fine Root Growth Phenology, Production, and Turnover in a Northern Hardwood Forest Ecosystem

    Treesearch

    Marianne K. Burke; Dudley J. Raynal

    1994-01-01

    A large part of the nutrient flux in deciduous forests is through fine root turnover, yet this process is seldom measured. As part of a nutrient cycling study, fine root dynamics were studied for two years at Huntington Forest in the Adirondack Mountain region of New York, USA. Root growth phenology was characterized using field rhizotrons, three methods were used to...

  11. Growth decline linked to warming-induced water limitation in hemi-boreal forests.

    PubMed

    Wu, Xiuchen; Liu, Hongyan; Guo, Dali; Anenkhonov, Oleg A; Badmaeva, Natalya K; Sandanov, Denis V

    2012-01-01

    Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal forests, based on ring width measurements from three dominant tree-species (Pinus sylvestris, Larix sibirica and Larix gmelinii), sampled from eight sites in the region. We found that regional tree growth has become increasingly limited by low soil water content in the pre- and early-growing season (from October of the previous year to July of the current year) over the past 80 years. A warming-induced reduction in soil water content has also increased the climate sensitivity of these three tree species. Beginning in the mid-1980s, a clear decline in growth is evident for both the pine forests and the larch forests, although there are increasing trends in the proxy of soil water use efficiencies. Our findings are consistent with those from other parts of the world and provide valuable insights into the regional carbon cycle and vegetation dynamics, and should be useful for devising adaptive forest management strategies.

  12. Increased water deficit decreases Douglas fir growth throughout western US forests

    Treesearch

    Christina M. Restaino; David L. Peterson; Jeremy Littell

    2016-01-01

    Changes in tree growth rates can affect tree mortality and forest feedbacks to the global carbon cycle. As air temperature increases, evaporative demand also increases, increasing effective drought in forest ecosystems. Using a spatially comprehensive network of Douglas fir (Pseudotsuga menziesii) chronologies from 122 locations that represent distinct climate...

  13. Estimating the capital recovery costs of managing for old growth forests

    Treesearch

    Chris B. LeDoux

    2004-01-01

    Contemporary forest management practices require a variety of retention treatments that leave clumps, blocks, strips, or zones of existing forest cover in order to achieve a wide array of biodiversity, wildlife, visual, ecological, and old growth creation/conservation objectives. Some of these practices call for leaving a portion or portions of existing stands for...

  14. Loblolly pine growth and soil nutrient stocks eight years after forest slash incorporation

    Treesearch

    Felipe G. Sanchez; Emily A. Carter; Zakiya H. Leggett

    2009-01-01

    Incorporation of forest slash during stand establishment is proposed as a means of increasing soil carbon and nutrient stocks. If effective, the increased soil carbon and nutrient status may result in increased aboveground tree growth. Eight years after study installation, the impact of forest slash incorporation into the soil on soil carbon and nutrient stocks, foliar...

  15. Alternative definitions of growth and removals and implications for forest sustainability

    Treesearch

    Paul C. Van Deusen; Francis A. Roesch

    2008-01-01

    Alternative definitions for growth and removals from a forest being monitored over time are discussed. It is shown that the definitions that are used in practice may not be what one would expect and estimates can vary substantially under alternative definitions. This can result in conclusions about forest sustainability that may be misleading. Alternative definitions...

  16. Growth Decline Linked to Warming-Induced Water Limitation in Hemi-Boreal Forests

    PubMed Central

    Wu, Xiuchen; Liu, Hongyan; Guo, Dali; Anenkhonov, Oleg A.; Badmaeva, Natalya K.; Sandanov, Denis V.

    2012-01-01

    Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal forests, based on ring width measurements from three dominant tree-species (Pinus sylvestris, Larix sibirica and Larix gmelinii), sampled from eight sites in the region. We found that regional tree growth has become increasingly limited by low soil water content in the pre- and early-growing season (from October of the previous year to July of the current year) over the past 80 years. A warming-induced reduction in soil water content has also increased the climate sensitivity of these three tree species. Beginning in the mid-1980s, a clear decline in growth is evident for both the pine forests and the larch forests, although there are increasing trends in the proxy of soil water use efficiencies. Our findings are consistent with those from other parts of the world and provide valuable insights into the regional carbon cycle and vegetation dynamics, and should be useful for devising adaptive forest management strategies. PMID:22916142

  17. Historical harvests reduce neighboring old-growth basal area across a forest landscape.

    PubMed

    Bell, David M; Spies, Thomas A; Pabst, Robert

    2017-07-01

    While advances in remote sensing have made stand, landscape, and regional assessments of the direct impacts of disturbance on forests quite common, the edge influence of timber harvesting on the structure of neighboring unharvested forests has not been examined extensively. In this study, we examine the impact of historical timber harvests on basal area patterns of neighboring old-growth forests to assess the magnitude and scale of harvest edge influence in a forest landscape of western Oregon, USA. We used lidar data and forest plot measurements to construct 30-m resolution live tree basal area maps in lower and middle elevation mature and old-growth forests. We assessed how edge influence on total, upper canopy, and lower canopy basal area varied across this forest landscape as a function of harvest characteristics (i.e., harvest size and age) and topographic conditions in the unharvested area. Upper canopy, lower canopy, and total basal area increased with distance from harvest edge and elevation. Forests within 75 m of harvest edges (20% of unharvested forests) had 4% to 6% less live tree basal area compared with forest interiors. An interaction between distance from harvest edge and elevation indicated that elevation altered edge influence in this landscape. We observed a positive edge influence at low elevations (<800 m) and a negative edge influence at moderate to high elevations (>800 m). Surprisingly, we found no or weak effects of harvest age (13-60 yr) and harvest area (0.2-110 ha) on surrounding unharvested forest basal area, implying that edge influence was relatively insensitive to the scale of disturbance and multi-decadal recovery processes. Our study indicates that the edge influence of past clearcutting on the structure of neighboring uncut old-growth forests is widespread and persistent. These indirect and diffuse legacies of historical timber harvests complicate forest management decision-making in old-growth forest landscapes by broadening

  18. Revision and application of the LINKAGES model to simulate forest growth in central hardwood landscapes in response to climate change

    Treesearch

    William D. Dijak; Brice B. Hanberry; Jacob S. Fraser; Hong S. He; Wen J. Wang; Frank R. Thompson

    2017-01-01

    Context. Global climate change impacts forest growth and methods of modeling those impacts at the landscape scale are needed to forecast future forest species composition change and abundance. Changes in forest landscapes will affect ecosystem processes and services such as succession and disturbance, wildlife habitat, and production of forest...

  19. Mature and old-growth riparian forests: structure, dynamics, and effects on Adirondack stream habitats.

    PubMed

    Keeton, William S; Kraft, Clifford E; Warren, Dana R

    2007-04-01

    Riparian forests regulate linkages between terrestrial and aquatic ecosystems, yet relationships among riparian forest development, stand structure, and stream habitats are poorly understood in many temperate deciduous forest systems. Our research has (1) described structural attributes associated with old-growth riparian forests and (2) assessed linkages between these characteristics and in-stream habitat structure. The 19 study sites were located along predominantly first- and second-order streams in northern hardwood-conifer forests in the Adirondack Mountains of New York (U.S.A.). Sites were classified as mature forest (6 sites), mature with remnant old-growth trees (3 sites), and old-growth (10 sites). Forest-structure attributes were measured over stream channels and at varying distances from each bank. In-stream habitat features such as large woody debris (LWD), pools, and boulders were measured in each stream reach. Forest structure was examined in relation to stand age using multivariate techniques, ANOVA, and linear regression. We investigated linkages between forest structure and stream characteristics using similar methods, preceded by information-theoretic modeling (AIC). Old-growth riparian forest structure is more complex than that found in mature forests and exhibits significantly greater accumulations of aboveground tree biomass, both living and dead. In-stream LWD volumes were significantly (alpha = 0.05) greater at old-growth sites (200 m3/ha) compared to mature sites (34 m3/ha) and were strongly related to the basal area of adjacent forests. In-stream large-log densities correlated strongly with debris-dam densities. AIC models that included large-log density, debris-dam density, boulder density, and bankfull width had the most support for predicting pool density. There were higher proportions of LWD-formed pools relative to boulder-formed pools at old-growth sites as compared to mature sites. Old-growth riparian forests provide in

  20. Assessments of wildlife viability, old-growth timber volume estimates, forested wetlands, and slope stability. Forest Service general technical report

    SciTech Connect

    Shaw, C.G.; Julin, K.R.

    1997-03-01

    Conceptual Approaches for Maintaining Well-Distributed Viable Wildlife Populations: A Resource Assessment; Options for Defining Old-Growth Timber Volume Strata: A Resource Assessment; Tentative Suitability of Forested Wetlands for Timber Production: A Resource Assessment; and Controlling Stability Characteristics of Steep Terrain With Discussion of Needed Standardization for Mass Movement Hazard Indexing: A Resource Assessment.

  1. Crown dynamics and wood production of Douglas-fir trees in an old-growth forest

    Treesearch

    H. Roaki Ishii; Stephen C. Sillett; Allyson L. Carroll

    2017-01-01

    Large trees are the most prominent structural features of old-growth forests, which are considered to be globally important carbon sinks. Because of their large size, estimates of biomass and growth of large trees are often based on ground-level measurements (e.g., diameter at breast height, DBH) and little is known about growth dynamics within the crown. As trees...

  2. An Old-Growth Definition for Dry and Dry-Mesic Oak-Pine Forests.

    Treesearch

    David L. White; F. Thomas. Lloyd

    1998-01-01

    Dry and dry-mesic oak-pine forests are widely distributed from New Jersey to Texas, but representative old-growth stands are rare. Historical accounts of composition, along with information from existing old-growth stands, were used to characterize this type. Shortleaf pine and white oak were the most widely distributed trees across all old-growth stands. Shortleaf was...

  3. The AFIS tree growth model for updating annual forest inventories in Minnesota

    Treesearch

    Margaret R. Holdaway

    2000-01-01

    As the Forest Service moves towards annual inventories, states may use model predictions of growth to update unmeasured plots. A tree growth model (AFIS) based on the scaled Weibull function and using the average-adjusted model form is presented. Annual diameter growth for four species was modeled using undisturbed plots from Minnesota's Aspen-Birch and Northern...

  4. Housing growth, forests, and public lands in Northern Wisconsin form 1940 to 2000

    Treesearch

    Roger B. Hammer; Susan I. Stewart; Todd J. Hawbaker; Volker C. Radeloff

    2009-01-01

    Rural, forested areas throughout the United States are experiencing strong housing growth with potentially detrimental impacts on the environment. In this paper, we quantify housing growth in Northern Wisconsin over the last sixty years to determine if growth rates were higher near public lands, which may represent an important recreational amenity. We used data from...

  5. Northwest Forest Plan–the first 20 years (1994-2013): status and trends of late-successional and old-growth forests

    Treesearch

    Raymond J. Davis; Janet L. Ohmann; Robert E. Kennedy; Warren B. Cohen; Matthew J. Gregory; Zhiqiang Yang; Heather M. Roberts; Andrew N. Gray; Thomas A. Spies

    2015-01-01

    This is the third in a series of periodic monitoring reports on LSOG or latesuccessional and old-growth (older) forest status trends on federally administered lands since implementation of the Northwest Forest Plan (NWFP or the Plan) in 1994. The objective of this monitoring is to determine if the NWFP is providing for conservation and management of older forests as...

  6. Assessments of wildlife viability, old-growth timber volume estimates, forested wetlands, and slope stability.

    Treesearch

    Kent R. Julin

    1997-01-01

    Resource assessments on wildlife viability, old-growth timber volume estimates, forested wetlands, and slope stability are presented. These assessments were used in the formulation of alternatives in the revision of the Tongass land management plan.

  7. Old-growth and mature forests near spotted owl nests in western Oregon

    NASA Technical Reports Server (NTRS)

    Ripple, William J.; Johnson, David H.; Hershey, K. T.; Meslow, E. Charles

    1995-01-01

    We investigated how the amount of old-growth and mature forest influences the selection of nest sites by northern spotted owls (Strix occidentalis caurina) in the Central Cascade Mountains of Oregon. We used 7 different plot sizes to compare the proportion of mature and old-growth forest between 30 nest sites and 30 random sites. The proportion of old-growth and mature forest was significantly greater at nests sites than at random sites for all plot sizes (P less than or equal to 0.01). Thus, management of the spotted owl might require setting the percentage of old-growth and mature forest retained from harvesting at least 1 standard deviation above the mean for the 30 nest sites we examined.

  8. Evaluation of forest management systems under risk of wildfire

    Treesearch

    Kari Hyytiainen; Robert G. Haight

    2010-01-01

    We evaluate the economic efficiency of even- and uneven-aged management systems under risk of wildfire. The management problems are formulated for a mixed-conifer stand and approximations of the optimal solutions are obtained using simulation optimization. The Northern Idaho variant of the Forest Vegetation Simulator and its Fire and Fuels Extension is used to predict...

  9. Random Forests for Evaluating Pedagogy and Informing Personalized Learning

    ERIC Educational Resources Information Center

    Spoon, Kelly; Beemer, Joshua; Whitmer, John C.; Fan, Juanjuan; Frazee, James P.; Stronach, Jeanne; Bohonak, Andrew J.; Levine, Richard A.

    2016-01-01

    Random forests are presented as an analytics foundation for educational data mining tasks. The focus is on course- and program-level analytics including evaluating pedagogical approaches and interventions and identifying and characterizing at-risk students. As part of this development, the concept of individualized treatment effects (ITE) is…

  10. A Comprehensive Evaluation of the Supreme Court's "Forest Grove" Decision?

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2013-01-01

    The article by Dixon, Eusebio, Turton, Wright, and Hale is entitled "Forest Grove School District v. T.A. Supreme Court Case: Implications for School Psychology Practice." Its implications are that a "comprehensive evaluation" under the Individuals with Disabilities Education Act (IDEA) requires assessment of the child's…

  11. EVALUATION OF METRIC PRECISION FOR A RIPARIAN FOREST SURVEY

    EPA Science Inventory

    This paper evaluates the performance of a protocol to monitor riparian forests in western Oregon based on the quality of the data obtained from a recent field survey. Precision and accuracy are the criteria used to determine the quality of 19 field metrics. The field survey con...

  12. Random Forests for Evaluating Pedagogy and Informing Personalized Learning

    ERIC Educational Resources Information Center

    Spoon, Kelly; Beemer, Joshua; Whitmer, John C.; Fan, Juanjuan; Frazee, James P.; Stronach, Jeanne; Bohonak, Andrew J.; Levine, Richard A.

    2016-01-01

    Random forests are presented as an analytics foundation for educational data mining tasks. The focus is on course- and program-level analytics including evaluating pedagogical approaches and interventions and identifying and characterizing at-risk students. As part of this development, the concept of individualized treatment effects (ITE) is…

  13. Soil Taxonomy and land evaluation for forest establishment

    Treesearch

    Haruyoshi Ikawa

    1992-01-01

    Soil Taxonomy, the United States system of soil classification, can be used for land evaluation for selected purposes. One use is forest establishment in the tropics, and the soil family category is especially functional for this purpose. The soil family is a bionomial name with descriptions usually of soil texture, mineralogy, and soil temperature classes. If the...

  14. A heat wave during leaf expansion severely reduces productivity and modifies seasonal growth patterns in a northern hardwood forest.

    PubMed

    Stangler, Dominik Florian; Hamann, Andreas; Kahle, Hans-Peter; Spiecker, Heinrich; Mäkelä, Annikki

    2017-01-31

    A useful approach to monitor tree response to climate change and environmental extremes is the recording of long-term time series of stem radial variations obtained with precision dendrometers. Here, we study the impact of environmental stress on seasonal growth dynamics and productivity of yellow birch (Betula alleghaniensis Britton) and sugar maple (Acer saccharum Marsh.) in the Great Lakes, St Lawrence forest region of Ontario. Specifically, we research the effects of a spring heat wave in 2010, and a summer drought in 2012 that occurred during the 2005–14 study period. We evaluated both growth phenology (onset, cessation, duration of radial growth, time of maximum daily growth rate) and productivity (monthly and seasonal average growth rates, maximum daily growth rate, tree-ring width) and tested for differences and interactions among species and years. Productivity of sugar maple was drastically compromised by a 3-day spring heat wave in 2010 as indicated by low growth rates, very early growth cessation and a lagged growth onset in the following year. Sugar maple also responded more sensitively than yellow birch to a prolonged drought period in July 2012, but final tree-ring width was not significantly reduced due to positive responses to above-average temperatures in the preceding spring. We conclude that sugar maple, a species that currently dominates northern hardwood forests, is vulnerable to heat wave disturbances during leaf expansion, which might occur more frequently under anticipated climate change.

  15. Growth and demography of Pinaleno high elevation forests

    Treesearch

    Christopher O' Connor; Donald A. Falk; Ann M. Lynch; Craig P. Wilcox; Thomas W. Swetnam; Tyson L. Swetnam

    2010-01-01

    The project goal is to understand how multiple disturbance events including fire, insect outbreaks, and climate variability interact in space and time, and how they combine to influence forest species composition, spatial structure, and tree population dynamics in high elevation forests of the Pinaleno Mountains. Information from each of these components is needed in...

  16. An Old-Growth Definition for Eastern Riverfront Forests

    Treesearch

    James S. Meadows; Gregory J. Nowacki

    1996-01-01

    Eastern riverfront forests fall into one of three types: (1) nearly pure eastern cottonwood stands, (2) nearly pure black willow stands, and (3) typical riverfront hardwood stands containing many species, but generally dominated by sycamore, pecan, green ash, sugarberry, and American elm. The eastern riverfront forest represents an intermediate successional stage...

  17. Diameter Growth Models Using Minnesota Forest Inventory and Analysis Data

    Treesearch

    Veronica C. Lessard; Ronald E. McRoberts; Margaret R. Holdaway

    2001-01-01

    The Forest Inventory and Analysis (FIA) program of the USDA Forest Service North Central Research Station (NCRS) has begun replacing the 12-to 13-yr periodic inventory cycles for the states in the North Central region with annual inventories featuring measurement of approximately 20% of all plots in each of the 11 states each year. State reports on summaries of the...

  18. Soil-calcium depletion linked to acid rain and forest growth in the eastern United States

    USGS Publications Warehouse

    Lawrence, Gregory B.; Huntington, T.G.

    1999-01-01

    Since the discovery of acid rain in the 1970's, scientists have been concerned that deposition of acids could cause depletion of calcium in forest soils. Research in the 1980's showed that the amount of calcium in forest soils is controlled by several factors that are difficult to measure. Further research in the 1990's, including several studies by the U.S. Geological Survey, has shown that (1) calcium in forest soils has decreased at locations in the northeastern and southeastern U.S., and (2) acid rain and forest growth (uptake of calcium from the soil by roots) are both factors contributing to calcium depletion.

  19. Spatial relationship of biomass and species distribution in an old-growth Pseudotsuga Tsuga forest.

    Treesearch

    Jiquan Chen; Bo Song; Mark Rudnicki; Melinda Moeur; Ken Bible; Malcolm North; Dave C. Shaw; Jerry F. Franklin; Dave M. Braun

    2003-01-01

    Old-growth forests are known for their complex and variable structure and function. In a 12-ha plot (300 m x 400 m) of an old-growth Douglas-fir forest within the T.T. Munger Research Natural Area in southern Washington, we mapped and recorded live/dead condition, species, and diameter at breast height to address the following objectives: (1) to quantify the...

  20. Net Assimilation Rate Determines the Growth Rates of 14 Species of Subtropical Forest Trees.

    PubMed

    Li, Xuefei; Schmid, Bernhard; Wang, Fei; Paine, C E Timothy

    2016-01-01

    Growth rates are of fundamental importance for plants, as individual size affects myriad ecological processes. We determined the factors that generate variation in RGR among 14 species of trees and shrubs that are abundant in subtropical Chinese forests. We grew seedlings for two years at four light levels in a shade-house experiment. We monitored the growth of every juvenile plant every two weeks. After one and two years, we destructively harvested individuals and measured their functional traits and gas-exchange rates. After calculating individual biomass trajectories, we estimated relative growth rates using nonlinear growth functions. We decomposed the variance in log(RGR) to evaluate the relationships of RGR with its components: specific leaf area (SLA), net assimilation rate (NAR) and leaf mass ratio (LMR). We found that variation in NAR was the primary determinant of variation in RGR at all light levels, whereas SLA and LMR made smaller contributions. Furthermore, NAR was strongly and positively associated with area-based photosynthetic rate and leaf nitrogen content. Photosynthetic rate and leaf nitrogen concentration can, therefore, be good predictors of growth in woody species.

  1. The dynamic of annual carbon allocation to wood in European forests is consistent with a combined source-sink limitation of growth: implications for modelling

    NASA Astrophysics Data System (ADS)

    Guillemot, J.; Martin-StPaul, N. K.; Dufrêne, E.; François, C.; Soudani, K.; Ourcival, J. M.; Delpierre, N.

    2015-02-01

    The extent to which forest growth is limited by carbon (C) supply (source control) or by cambial activity (sink control) will condition the response of trees to global changes. However, the physiological processes responsible for the limitation of forest growth are still under debate. The aim of this study is to evaluate the key drivers of the annual carbon allocation to wood along large soil and climate regional gradients in five tree species representative of the main European forest biomes (Fagus sylvatica, Quercus petraea, Quercus ilex, Quercus robur and Picea abies). Combining field measurements and process-based simulations at 49 sites (931 site-years), we assessed the stand biomass growth dependences at both inter-site and inter-annual scales. Specifically, the relative influence of forest C balance (source control), direct environmental control (water and temperature controls of sink activity) and allocation adjustments related to age, past climate conditions, competition intensity and soil nutrient availability on growth were quantified. The inter-site variability in stand C allocation to wood was predominantly driven by an age-related decline. The direct control of temperature or water stress on sink activity (i.e. independently from their effects on C supply) exerted a strong influence on the annual stand woody growth in all the species considered, including deciduous temperate species. The lagged effect of the past environment conditions was a significant driver of the annual C allocation to wood. Carbon supply appeared to strongly limit growth only in deciduous temperate species. We provide an evaluation of the spatio-temporal dynamics of annual carbon allocation to wood in European forests. Our study supports the premise that European forest growth is under a complex control including both source and sink limitations. The relative influences of the different growth drivers strongly vary across years and spatial ecological gradients. We suggest a

  2. Diffusion-controlled kinetics of carbon nanotube forest growth by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Louchev, Oleg A.; Laude, Thomas; Sato, Yoichiro; Kanda, Hisao

    2003-04-01

    A detailed theoretical study of carbon nanotube (NT) forest growth by chemical vapor deposition is given, including (i) ballistic mode of carbon species impingement into the NT surface, (ii) the carbon diffusion over NT surface and through the metal nanoparticle, and (iii) the temperature drop at the NT tip occurring with increase in NT length. For typical NT forest growth parameters the ballistic flux of carbon species impinging into the NT surface decays quasiexponentially within several microns from the top. A variety of feasible growth modes, ranging from linear to exponential versus time, is predicted agreeing well with reported experiments. The presence of a metal nanoparticle is shown to shift NT growth from being surface diffusion controlled to being controlled by bulk diffusion through the nanoparticle. For typical growth conditions the growth rate is shown to be controlled simultaneously by surface diffusion over NT surface and bulk diffusion of carbon through metal nanoparticle. However, even in specific cases where NT growth rate is controlled by bulk diffusion through the nanoparticle the initial stage may be controlled by surface diffusion, as revealed by the exponential change in NT length with time. A parametric study of the growth rate of NT forest with metal nanoparticles held at the NT tips as a function of temperature reveals the existence of a maximum near 1050-1100 K, agreeing with reported experimental data. A thermal analysis based upon the heat conductance equation shows that with NT forest growth the temperature of the NT tips decreases, leading to growth deceleration and termination. Our study shows that the larger the pressure the smaller the NT forest height that may be grown. In particular, for pressures ≈105 Pa the NT tips should be "frozen" even at a length of a few microns, disabling further NT growth. In contrast, under low pressures of ≈103 Pa NT forest of several dozens of microns may be successfully grown without significant

  3. Growth performance of planted mangroves in the Philippines: revisiting forest management strategies.

    PubMed

    Samson, Maricar S; Rollon, Rene N

    2008-06-01

    The effort toward restoring lost mangroves in the Philippines has been commendably immense, specifically during the past two decades. In light of such, it is important to evaluate outcomes and, where appropriate, apply the lessons learned to the current strategies in mangrove forest management. This article synthesizes the results from several research projects assessing the performance of planted mangroves across the country. Overall, there is a widespread tendency to plant mangroves in areas that are not the natural habitat of mangroves, converting mudflats, sandflats, and seagrass meadows into often monospecific Rhizophora mangrove forests. In these nonmangrove areas, the Rhizophora seedlings experienced high mortality. Of the few that survived (often through persistent and redundant replanting), the young Rhizophora individuals planted in these nonmangrove and often low intertidal zones had dismally stunted growth relative to the corresponding growth performance of individuals thriving at the high intertidal position and natural mangrove sites. From this evidence, this article argues that a more rational focus of the restoration effort should be the replanting of mangroves in the brackish-water aquaculture pond environments, the original habitat of mangroves. For such, a number of management options can be explored, the implementation of which will ultimately depend on the political will of local and national governments.

  4. Phosphorus limits Eucalyptus grandis seedling growth in an unburnt rain forest soil

    PubMed Central

    Tng, David Y. P.; Janos, David P.; Jordan, Gregory J.; Weber, Ellen; Bowman, David M. J. S.

    2014-01-01

    Although rain forest is characterized as pyrophobic, pyrophilic giant eucalypts grow as rain forest emergents in both temperate and tropical Australia. In temperate Australia, such eucalypts depend on extensive, infrequent fires to produce conditions suitable for seedling growth. Little is known, however, about constraints on seedlings of tropical giant eucalypts. We tested whether seedlings of Eucalyptus grandis experience edaphic constraints similar to their temperate counterparts. We hypothesized that phosphorous addition would alleviate edaphic constraints. We grew seedlings in a factorial experiment combining fumigation (to simulate nutrient release and soil pasteurization by fire), soil type (E. grandis forest versus rain forest soil) and phosphorus addition as factors. We found that phosphorus was the principal factor limiting E. grandis seedling survival and growth in rain forest soil, and that fumigation enhanced survival of seedlings in both E. grandis forest and rain forest soil. We conclude that similar to edaphic constraints on temperate giant eucalypts, mineral nutrient and biotic attributes of a tropical rain forest soil may hamper E. grandis seedling establishment. In rain forest soil, E. grandis seedlings benefited from conditions akin to a fire-generated ashbed (i.e., an “ashbed effect”). PMID:25339968

  5. Phosphorus limits Eucalyptus grandis seedling growth in an unburnt rain forest soil.

    PubMed

    Tng, David Y P; Janos, David P; Jordan, Gregory J; Weber, Ellen; Bowman, David M J S

    2014-01-01

    Although rain forest is characterized as pyrophobic, pyrophilic giant eucalypts grow as rain forest emergents in both temperate and tropical Australia. In temperate Australia, such eucalypts depend on extensive, infrequent fires to produce conditions suitable for seedling growth. Little is known, however, about constraints on seedlings of tropical giant eucalypts. We tested whether seedlings of Eucalyptus grandis experience edaphic constraints similar to their temperate counterparts. We hypothesized that phosphorous addition would alleviate edaphic constraints. We grew seedlings in a factorial experiment combining fumigation (to simulate nutrient release and soil pasteurization by fire), soil type (E. grandis forest versus rain forest soil) and phosphorus addition as factors. We found that phosphorus was the principal factor limiting E. grandis seedling survival and growth in rain forest soil, and that fumigation enhanced survival of seedlings in both E. grandis forest and rain forest soil. We conclude that similar to edaphic constraints on temperate giant eucalypts, mineral nutrient and biotic attributes of a tropical rain forest soil may hamper E. grandis seedling establishment. In rain forest soil, E. grandis seedlings benefited from conditions akin to a fire-generated ashbed (i.e., an "ashbed effect").

  6. An individual-based growth and competition model for coastal redwood forest restoration

    USGS Publications Warehouse

    van Mantgem, Phillip J.; Das, Adrian J.

    2014-01-01

    Thinning treatments to accelerate coastal redwood forest stand development are in wide application, but managers have yet to identify prescriptions that might best promote Sequoia sempervirens (Lamb. ex D. Don) Endl. (redwood) growth. The creation of successful thinning prescriptions would be aided by identifying the underlying mechanisms governing how individual tree growth responds to competitive environments in coastal redwood forests. We created a spatially explicit individual-based model of tree competition and growth parameterized using surveys of upland redwood forests at Redwood National Park, California. We modeled competition for overstory trees (stems ≥ 20 cm stem diameter at breast height, 1.37 m (dbh)) as growth reductions arising from sizes, distances, and species identity of competitor trees. Our model explained up to half of the variation in individual tree growth, suggesting that neighborhood crowding is an important determinant of growth in this forest type. We used our model to simulate the effects of novel thinning prescriptions (e.g., 40% stand basal area removal) for redwood forest restoration, concluding that these treatments could lead to substantial growth releases, particularly for S. sempervirens. The results of this study, along with continued improvements to our model, will help to determine spacing and species composition that best encourage growth.

  7. Evaluation of Forest Health Conditions using Unmanned Aircraft Systems (UAS)

    NASA Astrophysics Data System (ADS)

    Hatfield, M. C.; Heutte, T. M.

    2016-12-01

    US Forest Service Alaska Region Forest Health Protection (FHP) and University of Alaska Fairbanks, Alaska Center for Unmanned Aircraft Systems Integration (ACUASI) are evaluating capability of Unmanned Aerial Systems (UAS) to monitor forest health conditions in Alaska's Interior Region. In July 2016, the team deployed UAS at locations in the Tanana Valley near Fairbanks in order to familiarize FHP staff with capabilities of UAS for evaluating insect and disease damage. While many potential uses of UAS to evaluate and monitor forest health can be envisioned, this project focused on use of a small UAS for rapid assessment of insect and disease damage. Traditional ground-based methods are limited by distance from ground to canopy and inaccessibility of forest stands due to terrain conditions. Observation from fixed-wing aircraft provide a broad overview of conditions but are limited by minimum safe flying altitude (500' AGL) and aircraft speed ( 100 mph). UAS may provide a crucial bridge to fill in gaps between ground and airborne methods, and offer significant cost savings and greater flexibility over helicopter-based observations. Previous uses of UAS for forest health monitoring are limited - this project focuses on optimizing choice of vehicle, sensors, resolution and area scanned from different altitudes, and use of visual spectrum vs NIR image collection. The vehicle selected was the ACUASI Ptarmigan, a small hexacopter (based on DJI S800 airframe and 3DR autopilot) capable of carrying a 1.5 kg payload for 15 min for close-range environmental monitoring missions. Sites were chosen for conditions favorable to UAS operation and presence of forest insect and disease agents including spruce broom rust, aspen leaf miner, birch leaf roller, and willow leafblotch miner. A total of 29 flights were conducted with 9000+ images collected. Mission variables included camera height, UAS speed, and medium- (Sony NEX-7) vs low-resolution (GoPro Hero) cameras. Invaluable

  8. Georgia's forests, 1989

    Treesearch

    Raymond M. Sheffield; Tony G. Johnson

    1993-01-01

    This resource bulletin presents the principal findings of the sixth inventory of Georgia's forest resources. Data on the extent, condition, and classification of forest land and associated timber volumes, growth, removals, and mortality are described and interpreted. Whereas data on nontimber commodities associated with forests were also collected, evaluations of...

  9. South Carolina's forests

    Treesearch

    John B. Tansey; Cecil C. Hutchins

    1988-01-01

    This report presents the principal findings of the sixth evaluation of South Carolina's forest resources. Data concerning the extent and condition of forest land, associated timber volumes, and rates of growth and removals are included. In accordance with the Forest and Rangeland Renewable Resources Planning Act (RPA) of 1974, the sixth inventory of South Carolina...

  10. Steeper declines in forest photosynthesis than respiration explain age-driven decreases in forest growth.

    PubMed

    Tang, Jianwu; Luyssaert, Sebastiaan; Richardson, Andrew D; Kutsch, Werner; Janssens, Ivan A

    2014-06-17

    The traditional view of forest dynamics originated by Kira and Shidei [Kira T, Shidei T (1967) Jap J Ecol 17:70-87] and Odum [Odum EP (1969) Science 164(3877):262-270] suggests a decline in net primary productivity (NPP) in aging forests due to stabilized gross primary productivity (GPP) and continuously increased autotrophic respiration (Ra). The validity of these trends in GPP and Ra is, however, very difficult to test because of the lack of long-term ecosystem-scale field observations of both GPP and Ra. Ryan and colleagues [Ryan MG, Binkley D, Fownes JH (1997) Ad Ecol Res 27:213-262] have proposed an alternative hypothesis drawn from site-specific results that aboveground respiration and belowground allocation decreased in aging forests. Here, we analyzed data from a recently assembled global database of carbon fluxes and show that the classical view of the mechanisms underlying the age-driven decline in forest NPP is incorrect and thus support Ryan's alternative hypothesis. Our results substantiate the age-driven decline in NPP, but in contrast to the traditional view, both GPP and Ra decline in aging boreal and temperate forests. We find that the decline in NPP in aging forests is primarily driven by GPP, which decreases more rapidly with increasing age than Ra does, but the ratio of NPP/GPP remains approximately constant within a biome. Our analytical models describing forest succession suggest that dynamic forest ecosystem models that follow the traditional paradigm need to be revisited.

  11. Diverse growth trends and climate responses across Eurasia’s boreal forest

    NASA Astrophysics Data System (ADS)

    Hellmann, Lena; Agafonov, Leonid; Charpentier Ljungqvist, Fredrik; Churakova (Sidorova, Olga; Düthorn, Elisabeth; Esper, Jan; Hülsmann, Lisa; Kirdyanov, Alexander V.; Moiseev, Pavel; Myglan, Vladimir S.; Nikolaev, Anatoly N.; Reinig, Frederick; Schweingruber, Fritz H.; Solomina, Olga; Tegel, Willy; Büntgen, Ulf

    2016-07-01

    The area covered by boreal forests accounts for ˜16% of the global and 22% of the Northern Hemisphere landmass. Changes in the productivity and functioning of this circumpolar biome not only have strong effects on species composition and diversity at regional to larger scales, but also on the Earth’s carbon cycle. Although temporal inconsistency in the response of tree growth to temperature has been reported from some locations at the higher northern latitudes, a systematic dendroecological network assessment is still missing for most of the boreal zone. Here, we analyze the geographical patterns of changes in summer temperature and precipitation across northern Eurasia >60 °N since 1951 AD, as well as the growth trends and climate responses of 445 Pinus, Larix and Picea ring width chronologies in the same area and period. In contrast to widespread summer warming, fluctuations in precipitation and tree growth are spatially more diverse and overall less distinct. Although the influence of summer temperature on ring formation is increasing with latitude and distinct moisture effects are restricted to a few southern locations, growth sensitivity to June-July temperature variability is only significant at 16.6% of all sites (p ≤ 0.01). By revealing complex climate constraints on the productivity of Eurasia’s northern forests, our results question the a priori suitability of boreal tree-ring width chronologies for reconstructing summer temperatures. This study further emphasizes regional climate differences and their role on the dynamics of boreal ecosystems, and also underlines the importance of free data access to facilitate the compilation and evaluation of massively replicated and updated dendroecological networks.

  12. Interactions of climate and regional landscape physiography on high elevation forest growth

    NASA Astrophysics Data System (ADS)

    Kelsey, K.; Barger, N. N.; Neff, J. C.

    2014-12-01

    Forests of the western United States are in a period of rapid change, due in part to climate driven changes in life history processes of trees such as growth, establishment, and mortality. These changes in forest condition are of particular concern in the American Southwest where climate conditions are projected to become increasingly hot and dry throughout the next century. While lower elevation trees of the American Southwest are already experiencing decreased radial growth in response to moisture stress, the response of high elevation trees to future climate is highly uncertain. Here we use dendro-climatological techniques to explore the climate-mediated changes in radial tree growth over time in the high elevation forests of southwestern Colorado by sampling 450 Engelmann Spruce and 350 Subalpine Fir from 22 sites across varying aspect, elevation, slope and soil type. Our results indicate variable and frequently opposing growth responses of individuals of the same species to climate variables; 52% of Engelmann Spruce sampled (233 individuals) exhibited positive growth responses to warm summer monthly mean temperatures with the remaining 48% exhibiting negative growth response to warm summer temperatures. We found similarly opposing results for growth response to monthly precipitation and vapor pressure deficit. In this presentation we explore the physiological factors responsible for variable climate-growth relationships within these species. Our results suggest a complex response of high elevation forest growth to climate change, and indicate that efforts to constrain future growth in this region will be contingent on both climatic and local physiographic factors.

  13. The impact of atmospheric deposition and climate on forest growth in Europe using two empirical modelling approaches

    NASA Astrophysics Data System (ADS)

    Dobbertin, M.; Solberg, S.; Laubhann, D.; Sterba, H.; Reinds, G. J.; de Vries, W.

    2009-04-01

    Most recent studies show increasing forest growth in central Europe, rather than a decline as was expected due to negative effects of air pollution. While nitrogen deposition, increasing temperature and change in forest management are discussed as possible causes, quantification of the various environmental factors has rarely been undertaken. In our study, we used data from several hundreds of intensive monitoring plots from the ICP Forests network in Europe, ranging from northern Finland to Spain and southern Italy. Five-year growth data for the period 1994-1999 were available from roughly 650 plots to examine the influence of environmental factors on forest growth. Evaluations focused on the influence of nitrogen, sulphur and acid deposition, temperature, precipitation and drought. Concerning the latter meteorological variables we used the deviation from the long-term (30 years) mean. The study included the main tree species common beech (Fagus sylvatica), sessile or pedunculate oak (Quercus petraea and Q. robur), Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). Two very different approaches were used. In the first approach an individual tree-based regression model was applied (Laubhahn et al., 2009), while in the second approach a stand-based model was applied (Solberg et al., 2009). The individual tree-based model had measured basal area increment of each individual tree as a growth response variable and tree size (diameter at breast height), tree competition (basal area of larger trees and stand density index), site factors (e.g. soil C/N ratio, temperature), and environmental factors (e.g. temperature change compared to long-term average, nitrogen and sulphur deposition) as influencing parameters. In the stand-growth model, stem volume increment was used as the growth response variable, after filtering out the expected growth. Expected growth was modelled as a function of site productivity, stand age and a stand density index. Relative volume

  14. Attaining the canopy in dry and moist tropical forests: strong differences in tree growth trajectories reflect variation in growing conditions

    PubMed Central

    Zuidema, Pieter A.; Martínez-Ramos, Miguel

    2009-01-01

    Availability of light and water differs between tropical moist and dry forests, with typically higher understorey light levels and lower water availability in the latter. Therefore, growth trajectories of juvenile trees—those that have not attained the canopy—are likely governed by temporal fluctuations in light availability in moist forests (suppressions and releases), and by spatial heterogeneity in water availability in dry forests. In this study, we compared juvenile growth trajectories of Cedrela odorata in a dry (Mexico) and a moist forest (Bolivia) using tree rings. We tested the following specific hypotheses: (1) moist forest juveniles show more and longer suppressions, and more and stronger releases; (2) moist forest juveniles exhibit wider variation in canopy accession pattern, i.e. the typical growth trajectory to the canopy; (3) growth variation among dry forest juveniles persists over longer time due to spatial heterogeneity in water availability. As expected, the proportion of suppressed juveniles was higher in moist than in dry forest (72 vs. 17%). Moist forest suppressions also lasted longer (9 vs. 5 years). The proportion of juveniles that experienced releases in moist forest (76%) was higher than in dry forest (41%), and releases in moist forests were much stronger. Trees in the moist forest also had a wider variation in canopy accession patterns compared to the dry forest. Our results also showed that growth variation among juvenile trees persisted over substantially longer periods of time in dry forest (>64 years) compared to moist forest (12 years), most probably because of larger persistent spatial variation in water availability. Our results suggest that periodic increases in light availability are more important for attaining the canopy in moist forests, and that spatial heterogeneity in water availability governs long-term tree growth in dry forests. Electronic supplementary material The online version of this article (doi:10.1007/s

  15. Attaining the canopy in dry and moist tropical forests: strong differences in tree growth trajectories reflect variation in growing conditions.

    PubMed

    Brienen, Roel J W; Zuidema, Pieter A; Martínez-Ramos, Miguel

    2010-06-01

    Availability of light and water differs between tropical moist and dry forests, with typically higher understorey light levels and lower water availability in the latter. Therefore, growth trajectories of juvenile trees--those that have not attained the canopy--are likely governed by temporal fluctuations in light availability in moist forests (suppressions and releases), and by spatial heterogeneity in water availability in dry forests. In this study, we compared juvenile growth trajectories of Cedrela odorata in a dry (Mexico) and a moist forest (Bolivia) using tree rings. We tested the following specific hypotheses: (1) moist forest juveniles show more and longer suppressions, and more and stronger releases; (2) moist forest juveniles exhibit wider variation in canopy accession pattern, i.e. the typical growth trajectory to the canopy; (3) growth variation among dry forest juveniles persists over longer time due to spatial heterogeneity in water availability. As expected, the proportion of suppressed juveniles was higher in moist than in dry forest (72 vs. 17%). Moist forest suppressions also lasted longer (9 vs. 5 years). The proportion of juveniles that experienced releases in moist forest (76%) was higher than in dry forest (41%), and releases in moist forests were much stronger. Trees in the moist forest also had a wider variation in canopy accession patterns compared to the dry forest. Our results also showed that growth variation among juvenile trees persisted over substantially longer periods of time in dry forest (>64 years) compared to moist forest (12 years), most probably because of larger persistent spatial variation in water availability. Our results suggest that periodic increases in light availability are more important for attaining the canopy in moist forests, and that spatial heterogeneity in water availability governs long-term tree growth in dry forests.

  16. Gap characteristics of southeastern Ohio second-growth forests

    Treesearch

    David M. Hix; Katherine K. Helfrich

    2003-01-01

    Transect sampling was used to assess the features of 30 gaps encountered in upland oak stands on the Wayne National Forest. Tip-ups caused the most canopy gaps (52 percent), two-thirds of which were small (

  17. Forests synchronize their growth in contrasting Eurasian regions in response to climate warming

    PubMed Central

    Shestakova, Tatiana A.; Gutiérrez, Emilia; Kirdyanov, Alexander V.; Camarero, Jesús Julio; Génova, Mar; Knorre, Anastasia A.; Linares, Juan Carlos; Sánchez-Salguero, Raúl; Voltas, Jordi

    2016-01-01

    Forests play a key role in the carbon balance of terrestrial ecosystems. One of the main uncertainties in global change predictions lies in how the spatiotemporal dynamics of forest productivity will be affected by climate warming. Here we show an increasing influence of climate on the spatial variability of tree growth during the last 120 y, ultimately leading to unprecedented temporal coherence in ring-width records over wide geographical scales (spatial synchrony). Synchrony in growth patterns across cold-constrained (central Siberia) and drought-constrained (Spain) Eurasian conifer forests have peaked in the early 21st century at subcontinental scales (∼1,000 km). Such enhanced synchrony is similar to that observed in trees co-occurring within a stand. In boreal forests, the combined effects of recent warming and increasing intensity of climate extremes are enhancing synchrony through an earlier start of wood formation and a stronger impact of year-to-year fluctuations of growing-season temperatures on growth. In Mediterranean forests, the impact of warming on synchrony is related mainly to an advanced onset of growth and the strengthening of drought-induced growth limitations. Spatial patterns of enhanced synchrony represent early warning signals of climate change impacts on forest ecosystems at subcontinental scales. PMID:26729860

  18. Forests synchronize their growth in contrasting Eurasian regions in response to climate warming.

    PubMed

    Shestakova, Tatiana A; Gutiérrez, Emilia; Kirdyanov, Alexander V; Camarero, Jesús Julio; Génova, Mar; Knorre, Anastasia A; Linares, Juan Carlos; Resco de Dios, Víctor; Sánchez-Salguero, Raúl; Voltas, Jordi

    2016-01-19

    Forests play a key role in the carbon balance of terrestrial ecosystems. One of the main uncertainties in global change predictions lies in how the spatiotemporal dynamics of forest productivity will be affected by climate warming. Here we show an increasing influence of climate on the spatial variability of tree growth during the last 120 y, ultimately leading to unprecedented temporal coherence in ring-width records over wide geographical scales (spatial synchrony). Synchrony in growth patterns across cold-constrained (central Siberia) and drought-constrained (Spain) Eurasian conifer forests have peaked in the early 21st century at subcontinental scales (∼ 1,000 km). Such enhanced synchrony is similar to that observed in trees co-occurring within a stand. In boreal forests, the combined effects of recent warming and increasing intensity of climate extremes are enhancing synchrony through an earlier start of wood formation and a stronger impact of year-to-year fluctuations of growing-season temperatures on growth. In Mediterranean forests, the impact of warming on synchrony is related mainly to an advanced onset of growth and the strengthening of drought-induced growth limitations. Spatial patterns of enhanced synchrony represent early warning signals of climate change impacts on forest ecosystems at subcontinental scales.

  19. Structure and dynamics of an upland old- growth forest at Redwood National Park, California

    USGS Publications Warehouse

    van Mantgem, Philip J.; Stuart, John D.

    2011-01-01

    Many current redwood forest management targets are based on old-growth conditions, so it is critical that we understand the variability and range of conditions that constitute these forests. Here we present information on the structure and dynamics from six one-hectare forest monitoring plots in an upland old-growth forest at Redwood National Park, California. We surveyed all stems =20 cm DBH in 1995 and 2010, allowing us to estimate any systematic changes in these stands. Stem size distributions for all species and for redwood (Sequoia sempervirens (D. Don) Endl.) alone did not appreciably change over the 15 year observation interval. Recruitment and mortality rates were roughly balanced, as were basal area dynamics (gains from recruitment and growth versus losses from mortality). Similar patterns were found for Sequoia alone. The spatial structure of stems at the plots suggested a random distribution of trees, though the pattern for Sequoia alone was found to be significantly clumped at small scales (< 5 m) at three of the six plots. These results suggest that these forests, including populations of Sequoia, have been generally stable over the past 15 years at this site, though it is possible that fire exclusion may be affecting recruitment of smaller Sequoia (< 20 cm DBH). The non-uniform spatial arrangement of stems also suggests that restoration prescriptions for second-growth redwood forests that encourage uniform spatial arrangements do not appear to mimic current upland old-growth conditions.

  20. Involvement of allelopathy in inhibition of understory growth in red pine forests.

    PubMed

    Kato-Noguchi, Hisashi; Kimura, Fukiko; Ohno, Osamu; Suenaga, Kiyotake

    2017-07-12

    Japanese red pine (Pinus densiflora Sieb. et Zucc.) forests are characterized by sparse understory vegetation although sunlight intensity on the forest floor is sufficient for undergrowth. The possible involvement of pine allelopathy in the establishment of the sparse understory vegetation was investigated. The soil of the red pine forest floor had growth inhibitory activity on six test plant species including Lolium multiflorum, which was observed at the edge of the forest but not in the forest. Two growth inhibitory substances were isolated from the soil and characterized to be 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid. Those compounds are probably formed by degradation process of resin acids. Resin acids are produced by pine and delivered into the soil under the pine trees through balsam and defoliation. Threshold concentrations of 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid for the growth inhibition of L. multiflorum were 30 and 10μM, respectively. The concentrations of 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid in the soil were 312 and 397μM, respectively, which are sufficient concentrations to cause the growth inhibition because of the threshold. These results suggest that those compounds are able to work as allelopathic agents and may prevent from the invasion of herbaceous plants into the forests by inhibiting their growth. Therefore, allelopathy of red pine may be involved in the formation of the sparse understory vegetation. Copyright © 2017 Elsevier GmbH. All rights reserved.

  1. A synthesis of evaluation monitoring projects by the forest health monitoring program (1998-2007)

    Treesearch

    William A. Bechtold; Michael J. Bohne; Barbara L. Conkling; Dana L. Friedman; Borys M. Tkacz

    2012-01-01

    The national Forest Health Monitoring Program of the Forest Service, U.S. Department of Agriculture, has funded over 200 Evaluation Monitoring projects. Evaluation Monitoring is designed to verify and define the extent of deterioration in forest ecosystems where potential problems have been identified. This report is a synthesis of results from over 150 Evaluation...

  2. Comparing the plant diversity between artificial forest and nature growth forest in a giant panda habitat.

    PubMed

    Kang, Dongwei; Wang, Xiaorong; Li, Shuang; Li, Junqing

    2017-06-15

    Artificial restoration is an important way to restore forests, but little is known about its effect on the habitat restoration of the giant panda. In the present study, we investigated the characteristics of artificial forest in the Wanglang Nature Reserve to determine whether through succession it has formed a suitable habitat for the giant panda. We compared artificial forest characteristics with those of natural habitat used by the giant panda. We found that the dominant tree species in artificial forest differed from those in the natural habitat. The artificial forest had lower plant species richness and diversity in the tree and shrub layers than did the latter, and its community structure was characterized by smaller tree and bamboo sizes, and fewer and lower bamboo clumps, but more trees and larger shrub sizes. The typical community collocation of artificial forest was a "Picea asperata + no-bamboo" model, which differs starkly from the giant panda's natural habitat. After several years of restoration, the artificial forest has failed to become a suitable habitat for the giant panda. Therefore, a simple way of planting individual trees cannot restore giant panda habitat; instead, habitat restoration should be based on the habitat requirements of the giant panda.

  3. Global change induced biomass growth offsets carbon released via increased forest fire and respiration of the central Canadian boreal forest

    NASA Astrophysics Data System (ADS)

    Gonsamo, Alemu; Chen, Jing M.; Colombo, Stephen J.; Ter-Mikaelian, Michael T.; Chen, Jiaxin

    2017-05-01

    Northern boreal forests are sensitive to many effects of global change. This is of particular concern due to the proportionally greater climate change projected for the area in which these forests occur. One of the sensitive areas is the Far North of Ontario (FNO), consisting of one of the world's largest remaining tracts of unmanaged boreal forest, the world's third largest area of wetland, and the most southerly area of tundra. We studied past, present, and potential future carbon (C) balance of FNO forests using the Integrated Terrestrial Ecosystem Carbon Model and the Canadian Regional Climate Model with stand-replacing fire disturbance. The forced simulations of past (1901-2004) C balances indicated that vegetation C stock remained stable, while soil C stock gradually declined (-0.07 t C ha-1 yr-1, p < 0.001), resulting in an overall significant decrease in total ecosystem C balance (-0.07 t C ha-1 yr-1, p < 0.001). Two Representative Concentration Pathways (RCPs), RCP8.5 and RCP4.5, simulations of future (2007-2100) C balances indicated that the carbon dioxide fertilization and climate growth-enhancing effects of global change will outweigh C loss through increased ecosystem respiration, disturbance, and changes in forest age class structure resulting in an increase in total FNO ecosystem C stock by mid-21st century. However, the projected simulations also indicated that the relative sizes of forest C stocks will change, with relatively less in the soil and more in vegetation, increasing fuel loads and making the entire ecosystem susceptible to forest fire and insect disturbances.

  4. Long-term growth of temperate broadleaved forests no longer benefits soil C accumulation

    PubMed Central

    Ji, Yu-he; Guo, Ke; Fang, Shi-bo; Xu, Xiao-niu; Wang, Zhi-gao; Wang, Shu-dong

    2017-01-01

    It is widely recognized that the long-term growth of forests benefits biomass carbon (C) sequestration, but it is not known whether the long-term growth of forests would also benefit soil C sequestration. We selected 79 representative soil profiles and investigated the influence of the forest stand age on the soil C dynamics of three soil layers (0–10, 10–20 and 20–30 cm) in temperate broadleaved forests in East China. The results suggest that the soil C density in temperature broadleaved forests significantly changes with the stand age, following a convex parabolic curve. At an early stand age, the soil C density usually increases, reaching its peak value at a pre-mature stand age (approximately 50 years old). At later stand ages, the soil C density usually decreases. Therefore, our results reveal a turning point in the soil C density at a pre-mature stand age. The long-term growth of temperate broadleaved forests after pre-mature stand age no longer benefits soil C accumulation, probably promotes topsoil C loss. In addition, we found that the soil C density in the upper soil layer usually changes with the forest stand development more significantly than that in deeper soil layers. PMID:28176873

  5. Long-term growth of temperate broadleaved forests no longer benefits soil C accumulation

    NASA Astrophysics Data System (ADS)

    Ji, Yu-He; Guo, Ke; Fang, Shi-Bo; Xu, Xiao-Niu; Wang, Zhi-Gao; Wang, Shu-Dong

    2017-02-01

    It is widely recognized that the long-term growth of forests benefits biomass carbon (C) sequestration, but it is not known whether the long-term growth of forests would also benefit soil C sequestration. We selected 79 representative soil profiles and investigated the influence of the forest stand age on the soil C dynamics of three soil layers (0-10, 10-20 and 20-30 cm) in temperate broadleaved forests in East China. The results suggest that the soil C density in temperature broadleaved forests significantly changes with the stand age, following a convex parabolic curve. At an early stand age, the soil C density usually increases, reaching its peak value at a pre-mature stand age (approximately 50 years old). At later stand ages, the soil C density usually decreases. Therefore, our results reveal a turning point in the soil C density at a pre-mature stand age. The long-term growth of temperate broadleaved forests after pre-mature stand age no longer benefits soil C accumulation, probably promotes topsoil C loss. In addition, we found that the soil C density in the upper soil layer usually changes with the forest stand development more significantly than that in deeper soil layers.

  6. Long-term growth of temperate broadleaved forests no longer benefits soil C accumulation.

    PubMed

    Ji, Yu-He; Guo, Ke; Fang, Shi-Bo; Xu, Xiao-Niu; Wang, Zhi-Gao; Wang, Shu-Dong

    2017-02-08

    It is widely recognized that the long-term growth of forests benefits biomass carbon (C) sequestration, but it is not known whether the long-term growth of forests would also benefit soil C sequestration. We selected 79 representative soil profiles and investigated the influence of the forest stand age on the soil C dynamics of three soil layers (0-10, 10-20 and 20-30 cm) in temperate broadleaved forests in East China. The results suggest that the soil C density in temperature broadleaved forests significantly changes with the stand age, following a convex parabolic curve. At an early stand age, the soil C density usually increases, reaching its peak value at a pre-mature stand age (approximately 50 years old). At later stand ages, the soil C density usually decreases. Therefore, our results reveal a turning point in the soil C density at a pre-mature stand age. The long-term growth of temperate broadleaved forests after pre-mature stand age no longer benefits soil C accumulation, probably promotes topsoil C loss. In addition, we found that the soil C density in the upper soil layer usually changes with the forest stand development more significantly than that in deeper soil layers.

  7. Managing burned landscapes: Evaluating future management strategies for resilient forests under a warming climate

    Treesearch

    K. L. Shive; P. Z. Fule; C. H. Sieg; B. A. Strom; M. E. Hunter

    2014-01-01

    Climate change effects on forested ecosystems worldwide include increases in drought-related mortality, changes to disturbance regimes and shifts in species distributions. Such climate-induced changes will alter the outcomes of current management strategies, complicating the selection of appropriate strategies to promote forest resilience. We modelled forest growth in...

  8. Persistence of Native Trees in an Invaded Hawaiian Lowland Wet Forest: Experimental Evaluation of Light and Water Constraints

    Treesearch

    Jodie R. Schulten; T. Colleen Cole; Susan Cordell; Keiko M. Publico; Rebecca Ostertag; Jaime E. Enoka; Jené D. Michaud

    2014-01-01

    Hawaiian lowland wet forests are heavily invaded and their restoration is most likely to be successful if native species selected for restoration have efficient resource-use traits. We evaluated growth, survival, and ecophysiological responses of four native and four invasive species in a greenhouse experiment that simulated reduced light and water conditions commonly...

  9. Sentinel Mission: Forest Fire Products Evaluation over China

    NASA Astrophysics Data System (ADS)

    Garcia, M.; Sanz, J.; Salvador, P.; Molina, V.; Cassanova, J.-P.; Qin, Xianlin

    2016-08-01

    Sentinel-2a and Sentinel-3a were launch the 23 June 2015 and 16 February 2016 respectively. These two platforms constitute a great improvement in the surface monitoring, especially in forest fires emergency management, evaluation and recovery.The multispectral sensor on board Sentinel-2a is a perfect tool to delineate burnt areas and identify severity with great spatial and temporal resolution while the surface thermal information provided by Sea and Land Surface Temperature Radiometer (SLSTR) on board Sentinel-3a constitute a source of hotspots. Both platforms will be complemented with their respective twins Sentinel-2b and Sentinel-3b in order to improve temporal resolution.This work tries to evaluate the constellation capacity to provide reliable forest fires products over China by comparison with Earth Observing System (EOS) and Landsat constellation products.

  10. Rapid warming accelerates tree growth decline in semi-arid forests of Inner Asia.

    PubMed

    Liu, Hongyan; Park Williams, A; Allen, Craig D; Guo, Dali; Wu, Xiuchen; Anenkhonov, Oleg A; Liang, Eryuan; Sandanov, Denis V; Yin, Yi; Qi, Zhaohuan; Badmaeva, Natalya K

    2013-08-01

    Forests around the world are subject to risk of high rates of tree growth decline and increased tree mortality from combinations of climate warming and drought, notably in semi-arid settings. Here, we assess how climate warming has affected tree growth in one of the world's most extensive zones of semi-arid forests, in Inner Asia, a region where lack of data limits our understanding of how climate change may impact forests. We show that pervasive tree growth declines since 1994 in Inner Asia have been confined to semi-arid forests, where growing season water stress has been rising due to warming-induced increases in atmospheric moisture demand. A causal link between increasing drought and declining growth at semi-arid sites is corroborated by correlation analyses comparing annual climate data to records of tree-ring widths. These ring-width records tend to be substantially more sensitive to drought variability at semi-arid sites than at semi-humid sites. Fire occurrence and insect/pathogen attacks have increased in tandem with the most recent (2007-2009) documented episode of tree mortality. If warming in Inner Asia continues, further increases in forest stress and tree mortality could be expected, potentially driving the eventual regional loss of current semi-arid forests. © 2013 John Wiley & Sons Ltd.

  11. Tree growth acceleration and expansion of alpine forests: The synergistic effect of atmospheric and edaphic change

    PubMed Central

    Silva, Lucas C. R.; Sun, Geng; Zhu-Barker, Xia; Liang, Qianlong; Wu, Ning; Horwath, William R.

    2016-01-01

    Many forest ecosystems have experienced recent declines in productivity; however, in some alpine regions, tree growth and forest expansion are increasing at marked rates. Dendrochronological analyses at the upper limit of alpine forests in the Tibetan Plateau show a steady increase in tree growth since the early 1900s, which intensified during the 1930s and 1960s, and have reached unprecedented levels since 1760. This recent growth acceleration was observed in small/young and large/old trees and coincided with the establishment of trees outside the forest range, reflecting a connection between the physiological performance of dominant species and shifts in forest distribution. Measurements of stable isotopes (carbon, oxygen, and nitrogen) in tree rings indicate that tree growth has been stimulated by the synergistic effect of rising atmospheric CO2 and a warming-induced increase in water and nutrient availability from thawing permafrost. These findings illustrate the importance of considering soil-plant-atmosphere interactions to understand current and anticipate future changes in productivity and distribution of forest ecosystems. PMID:27652334

  12. Diverging climate trends in Mongolian taiga forests influence growth and regeneration of Larix sibirica

    PubMed Central

    Dulamsuren, Choimaa; Khishigjargal, Mookhor; Leuschner, Hanns Hubert; Leuschner, Christoph

    2010-01-01

    Central and semiarid north-eastern Asia was subject to twentieth century warming far above the global average. Since forests of this region occur at their drought limit, they are particularly vulnerable to climate change. We studied the regional variations of temperature and precipitation trends and their effects on tree growth and forest regeneration in Mongolia. Tree-ring series from more than 2,300 trees of Siberian larch (Larix sibirica) collected in four regions of Mongolia’s forest zone were analyzed and related to available weather data. Climate trends underlie a remarkable regional variation leading to contrasting responses of tree growth in taiga forests even within the same mountain system. Within a distance of a few hundred kilometers (140–490 km), areas with recently reduced growth and regeneration of larch alternated with regions where these parameters remained constant or even increased. Reduced productivity could be correlated with increasing summer temperatures and decreasing precipitation; improved growth conditions were found at increasing precipitation, but constant summer temperatures. An effect of increasing winter temperatures on tree-ring width or forest regeneration was not detectable. Since declines of productivity and regeneration are more widespread in the Mongolian taiga than the opposite trend, a net loss of forests is likely to occur in the future, as strong increases in temperature and regionally differing changes in precipitation are predicted for the twenty-first century. PMID:20571829

  13. Diverging climate trends in Mongolian taiga forests influence growth and regeneration of Larix sibirica.

    PubMed

    Dulamsuren, Choimaa; Hauck, Markus; Khishigjargal, Mookhor; Leuschner, Hanns Hubert; Leuschner, Christoph

    2010-08-01

    Central and semiarid north-eastern Asia was subject to twentieth century warming far above the global average. Since forests of this region occur at their drought limit, they are particularly vulnerable to climate change. We studied the regional variations of temperature and precipitation trends and their effects on tree growth and forest regeneration in Mongolia. Tree-ring series from more than 2,300 trees of Siberian larch (Larix sibirica) collected in four regions of Mongolia's forest zone were analyzed and related to available weather data. Climate trends underlie a remarkable regional variation leading to contrasting responses of tree growth in taiga forests even within the same mountain system. Within a distance of a few hundred kilometers (140-490 km), areas with recently reduced growth and regeneration of larch alternated with regions where these parameters remained constant or even increased. Reduced productivity could be correlated with increasing summer temperatures and decreasing precipitation; improved growth conditions were found at increasing precipitation, but constant summer temperatures. An effect of increasing winter temperatures on tree-ring width or forest regeneration was not detectable. Since declines of productivity and regeneration are more widespread in the Mongolian taiga than the opposite trend, a net loss of forests is likely to occur in the future, as strong increases in temperature and regionally differing changes in precipitation are predicted for the twenty-first century.

  14. Tree growth acceleration and expansion of alpine forests: The synergistic effect of atmospheric and edaphic change.

    PubMed

    Silva, Lucas C R; Sun, Geng; Zhu-Barker, Xia; Liang, Qianlong; Wu, Ning; Horwath, William R

    2016-08-01

    Many forest ecosystems have experienced recent declines in productivity; however, in some alpine regions, tree growth and forest expansion are increasing at marked rates. Dendrochronological analyses at the upper limit of alpine forests in the Tibetan Plateau show a steady increase in tree growth since the early 1900s, which intensified during the 1930s and 1960s, and have reached unprecedented levels since 1760. This recent growth acceleration was observed in small/young and large/old trees and coincided with the establishment of trees outside the forest range, reflecting a connection between the physiological performance of dominant species and shifts in forest distribution. Measurements of stable isotopes (carbon, oxygen, and nitrogen) in tree rings indicate that tree growth has been stimulated by the synergistic effect of rising atmospheric CO2 and a warming-induced increase in water and nutrient availability from thawing permafrost. These findings illustrate the importance of considering soil-plant-atmosphere interactions to understand current and anticipate future changes in productivity and distribution of forest ecosystems.

  15. Grow--a computer subroutine that projects the growth of trees in the Lake States' forests.

    Treesearch

    Gary J. Brand

    1981-01-01

    A computer subroutine, Grow, has been written in 1977 Standard FORTRAN to implement a distance-independent, individual tree growth model for Lake States' forests. Grow is a small and easy-to-use version of the growth model. All the user has to do is write a calling program to read initial conditions, call Grow, and summarize the results.

  16. Diameter growth performance of tree functional groups in Puerto Rican secondary tropical forests.

    Treesearch

    Patricia Adame; Maria Uriarte; Thomas Brandeis

    2014-01-01

    Aim of study: Understanding the factors that control tree growth in successional stands is particularly important for quantifying the carbon sequestration potential and timber yield of secondary tropical forests. Understanding the factors that control tree growth in successional stands is particularly important for quantifying the carbon sequestration potential and...

  17. ABOVE- AND BELOWGROUND CONTROLS ON FOREST TREE GROWTH, MORTALITY AND SPATIAL PATTERN

    EPA Science Inventory

    We investigated the relative importance of above- and belowground competition in controlling growth, mortality and spatial patterns of trees in a nitrogen-limited, old-growth forest in western Oregon. To assess the effects of competition for light, we applied a spatially-explici...

  18. Effects of intensive forest management practices on insect infestation levels and loblolly pine growth

    Treesearch

    John T. Nowak; C. Wayne Berisford

    2000-01-01

    Intensive forest management practices have been shown to increase tree growth and shorten rotation time. However, they may also lead to an increased need for insect pest management because of higher infestation levels and lower action thresholds. To investigate the relationship between intensive management practices arid insect infestation, maximum growth potential...

  19. A Long-Term View of Old-Growth Deciduous Forests

    Treesearch

    James T. Tanner; Paul B. Hamel

    2001-01-01

    Lowland old-growth forests in the Southeastern United States and Eastern Europe (Poland) survived because of accidents of history, topography, and ownership until they came under governmental protection. Such old-growth stands are the similar the world over; they have trees of many ages, patchy distribution of habitats, and a variety of microhabitats, all of which...

  20. ABOVE- AND BELOWGROUND CONTROLS ON FOREST TREE GROWTH, MORTALITY AND SPATIAL PATTERN

    EPA Science Inventory

    We investigated the relative importance of above- and belowground competition in controlling growth, mortality and spatial patterns of trees in a nitrogen-limited, old-growth forest in western Oregon. To assess the effects of competition for light, we applied a spatially-explici...

  1. Formulating a stand-growth model for mathematical programming problems in Appalachian forests

    Treesearch

    Gary W. Miller; Jay Sullivan

    1993-01-01

    Some growth and yield simulators applicable to central hardwood forests can be formulated for use in mathematical programming models that are designed to optimize multi-stand, multi-resource management problems. Once in the required format, growth equations serve as model constraints, defining the dynamics of stand development brought about by harvesting decisions. In...

  2. Stand density guides for predicting growth of forest tress of southwest Idaho

    Treesearch

    Douglas D. Basford; John Sloan; Joy Roberts

    2010-01-01

    This paper presents a method for estimating stand growth from stand density and average diameter in stands of pure and mixed species in Southwest Idaho. The methods are adapted from a model developed for Douglas-fir, ponderosa pine, and lodgepole pine on the Salmon National Forest. Growth data were derived from ponderosa pine increment cores taken from sample plots on...

  3. Quantifying Forest Soil Physical Variables Potentially Important for Site Growth Analyses

    Treesearch

    John S. Kush; Douglas G. Pitt; Phillip J. Craul; William D. Boyer

    2004-01-01

    Accurate mean plot values of forest soil factors are required for use as independent variables in site-growth analyses. Adequate accuracy is often difficult to attain because soils are inherently widely variable. Estimates of the variability of appropriate soil factors influencing growth can be used to determine the sampling intensity required to secure accurate mean...

  4. An evaluation of imaging spectrometry for estimating forest canopy chemistry

    NASA Technical Reports Server (NTRS)

    Wessman, Carol A.; Aber, John D.; Peterson, David L.

    1989-01-01

    High spectral resolution Airborne Imaging Spectrometer (AIS) data were acquired over 20 well-studied Wisconsin forest sites to evaluate the potential of remote sensing for estimating forest canopy chemistry. Intensive nutrient cycling research in these forests demonstrates that canopy lignin content is strongly related to measured annual nitrogen mineralization at the undisturbed sites and may serve as an accurate index for nitrogen cycling rates. Ground measurements were made of foliar biomass and canopy nitrogen and lignin content, the latter within two weeks of the AIS overflight. The spectral data were transformed using derivative techniques modified from laboratroy spectroscopy. Stepwise regression assisted in determining combinations of wavelengths most highly correlated with canopy chemistry and biomass. Strong correlations between AIS data and total canopy lignin content in deciduous forests and canopy lignin concentration (total lignin/biomass) in both deciduous and coniferous stands indicate that imaging spectrometry can be used to estimate canopy lignin content and, from that, the spatial distribution of annual nitrogen mineralization rates.

  5. An evaluation of imaging spectrometry for estimating forest canopy chemistry

    NASA Technical Reports Server (NTRS)

    Wessman, Carol A.; Aber, John D.; Peterson, David L.

    1989-01-01

    High spectral resolution Airborne Imaging Spectrometer (AIS) data were acquired over 20 well-studied Wisconsin forest sites to evaluate the potential of remote sensing for estimating forest canopy chemistry. Intensive nutrient cycling research in these forests demonstrates that canopy lignin content is strongly related to measured annual nitrogen mineralization at the undisturbed sites and may serve as an accurate index for nitrogen cycling rates. Ground measurements were made of foliar biomass and canopy nitrogen and lignin content, the latter within two weeks of the AIS overflight. The spectral data were transformed using derivative techniques modified from laboratroy spectroscopy. Stepwise regression assisted in determining combinations of wavelengths most highly correlated with canopy chemistry and biomass. Strong correlations between AIS data and total canopy lignin content in deciduous forests and canopy lignin concentration (total lignin/biomass) in both deciduous and coniferous stands indicate that imaging spectrometry can be used to estimate canopy lignin content and, from that, the spatial distribution of annual nitrogen mineralization rates.

  6. The process-based stand growth model Formix 3-Q applied in a GIS environment for growth and yield analysis in a tropical rain forest.

    PubMed

    Ditzer, T.; Glauner, R.; Förster, M.; Köhler, P.; Huth, A.

    2000-03-01

    Managing tropical rain forests is difficult because few long-term field data on forest growth and the impact of harvesting disturbance are available. Growth models may provide a valuable tool for managers of tropical forests, particularly if applied to the extended forest areas of up to 100,000 ha that typically constitute the so-called forest management units (FMUs). We used a stand growth model in a geographic information system (GIS) environment to simulate tropical rain forest growth at the FMU level. We applied the process-based rain forest growth model Formix 3-Q to the 55,000 ha Deramakot Forest Reserve (DFR) in Sabah, Malaysia. The FMU was considered to be composed of single and independent small-scale stands differing in site conditions and forest structure. Field data, which were analyzed with a GIS, comprised a terrestrial forest inventory, site and soil analyses (water, nutrients, slope), the interpretation of aerial photographs of the present vegetation and topographic maps. Different stand types were determined based on a classification of site quality (three classes), slopes (four classes), and present forest structure (four strata). The effects of site quality on tree allometry (height-diameter curve, biomass allometry, leaf area) and growth (increment size) are incorporated into Formix 3-Q. We derived allometric relations and growth factors for different site conditions from the field data. Climax forest structure at the stand level was shown to depend strongly on site conditions. Simulated successional pattern and climax structure were compared with field observations. Based on the current management plan for the DFR, harvesting scenarios were simulated for stands on different sites. The effects of harvesting guidelines on forest structure and the implications for sustainable forest management at Deramakot were analyzed. Based on the stand types and GIS analysis, we also simulated undisturbed regeneration of the logged-over forest in the DFR at

  7. Candidate old-growth on national forest system administered lands in California since the initiation of national forest management

    Treesearch

    William F. Laudenslayer

    1985-01-01

    The following is a report on the status of Candidate Old-growth (hereafter identified as COG) on National Forest System administered lands in California in the past, a t present, and in the immediate fhture. These r e s u l t s are based on information that may be speculative and contain inconsistencies, and therefore must be treated with caution. COG on these lands...

  8. Evaluating differences in forest fragmentation and restoration between western natural forests and southeastern plantation forests in the United States.

    PubMed

    Ren, Xinyu; Lv, Yingying; Li, Mingshi

    2017-03-01

    Changes in forest ecosystem structure and functions are considered some of the research issues in landscape ecology. In this study, advancing Forman's theory, we considered five spatially explicit processes associated with fragmentation, including perforation, dissection, subdivision, shrinkage, and attrition, and two processes associated with restoration, i.e., increment and expansion processes. Following this theory, a forest fragmentation and restoration process model that can detect the spatially explicit processes and ecological consequences of forest landscape change was developed and tested in the current analysis. Using the National Land Cover Databases (2001, 2006 and 2011), the forest fragmentation and restoration process model was applied to US western natural forests and southeastern plantation forests to quantify and classify forest patch losses into one of the four fragmentation processes (the dissection process was merged into the subdivision process) and to classify the newly gained forest patches based on the two restoration processes. At the same time, the spatio-temporal differences in fragmentation and restoration patterns and trends between natural forests and plantations were further compared. Then, through overlaying the forest fragmentation/restoration processes maps with targeting year land cover data and land ownership vectors, the results from forest fragmentation and the contributors to forest restoration in federal and nonfederal lands were identified. Results showed that, in natural forests, the forest change patches concentrated around the urban/forest, cultivated/forest, and shrubland/forest interfaces, while the patterns of plantation change patches were scattered sparsely and irregularly. The shrinkage process was the most common type in forest fragmentation, and the average size was the smallest. Expansion, the most common restoration process, was observed in both natural forests and plantations and often occurred around the

  9. Low temperature growth of ultra-high mass density carbon nanotube forests on conductive supports

    SciTech Connect

    Sugime, Hisashi; Esconjauregui, Santiago; Yang, Junwei; D'Arsié, Lorenzo; Robertson, John; Oliver, Rachel A.; Bhardwaj, Sunil; Cepek, Cinzia

    2013-08-12

    We grow ultra-high mass density carbon nanotube forests at 450 °C on Ti-coated Cu supports using Co-Mo co-catalyst. X-ray photoelectron spectroscopy shows Mo strongly interacts with Ti and Co, suppressing both aggregation and lifting off of Co particles and, thus, promoting the root growth mechanism. The forests average a height of 0.38 μm and a mass density of 1.6 g cm{sup −3}. This mass density is the highest reported so far, even at higher temperatures or on insulators. The forests and Cu supports show ohmic conductivity (lowest resistance ∼22 kΩ), suggesting Co-Mo is useful for applications requiring forest growth on conductors.

  10. Seedling growth responses to soil resources in the understory of a wet tropical forest.

    PubMed

    Holste, Ellen K; Kobe, Richard K; Vriesendorp, Corine F

    2011-09-01

    Plant growth responses to resources may be an important mechanism that influences species' distributions, coexistence, and community structure. Irradiance is considered the most important resource for seedling growth in the understory of wet tropical forests, but multiple soil nutrients and species have yet to be examined simultaneously with irradiance under field conditions. To identify potentially limiting resources, we modeled tree seedling growth as a function of irradiance and soil nutrients across five sites, spanning a soil fertility gradient in old-growth, wet tropical forests at La Selva Biological Station, Costa Rica. We measured an array of soil nutrients including total nitrogen (total N), inorganic N (nitrate [NO3-] and ammonium [NH4+]), phosphate (PO4-), and sum of base cations (SBC; potassium, magnesium, and calcium). Shade in the forest understory did not preclude seedling growth correlations with soil nutrients. Irradiance was a significant predictor of growth in 52% of the species, inorganic N in 54% (NO3- in 32%; NH4+ in 34%), total N in 47%, SBC in 39%, and PO4- in 29%. Overall, growth was correlated with both irradiance and soil nutrients in 45% of species and with soil nutrients only in an additional 48%; rarely was irradiance alone correlated with growth. Contrary to expectations, the magnitudes of growth effects, assessed as the maximum growth response to significant resources for each species, were similar for irradiance and most soil nutrients. Among species whose growth correlated with soil nutrients, the rank importance of nutrient effects was SBC, followed by N (total N, NO3-, and/or NH4+) and PO4-. Species' growth responsiveness (i.e., magnitudes of effect) to irradiance and soil nutrients was negatively correlated with species' shade tolerance (survival under 1% full sun). In this broad survey of species and resources, the nearly ubiquitous effects of soil nutrients on seedling growth challenge the idea that soil nutrients are less

  11. Re-evaluation of forest biomass carbon stocks and lessons from the world's most carbon-dense forests.

    PubMed

    Keith, Heather; Mackey, Brendan G; Lindenmayer, David B

    2009-07-14

    From analysis of published global site biomass data (n = 136) from primary forests, we discovered (i) the world's highest known total biomass carbon density (living plus dead) of 1,867 tonnes carbon per ha (average value from 13 sites) occurs in Australian temperate moist Eucalyptus regnans forests, and (ii) average values of the global site biomass data were higher for sampled temperate moist forests (n = 44) than for sampled tropical (n = 36) and boreal (n = 52) forests (n is number of sites per forest biome). Spatially averaged Intergovernmental Panel on Climate Change biome default values are lower than our average site values for temperate moist forests, because the temperate biome contains a diversity of forest ecosystem types that support a range of mature carbon stocks or have a long land-use history with reduced carbon stocks. We describe a framework for identifying forests important for carbon storage based on the factors that account for high biomass carbon densities, including (i) relatively cool temperatures and moderately high precipitation producing rates of fast growth but slow decomposition, and (ii) older forests that are often multiaged and multilayered and have experienced minimal human disturbance. Our results are relevant to negotiations under the United Nations Framework Convention on Climate Change regarding forest conservation, management, and restoration. Conserving forests with large stocks of biomass from deforestation and degradation avoids significant carbon emissions to the atmosphere, irrespective of the source country, and should be among allowable mitigation activities. Similarly, management that allows restoration of a forest's carbon sequestration potential also should be recognized.

  12. Re-evaluation of forest biomass carbon stocks and lessons from the world's most carbon-dense forests

    PubMed Central

    Keith, Heather; Mackey, Brendan G.; Lindenmayer, David B.

    2009-01-01

    From analysis of published global site biomass data (n = 136) from primary forests, we discovered (i) the world's highest known total biomass carbon density (living plus dead) of 1,867 tonnes carbon per ha (average value from 13 sites) occurs in Australian temperate moist Eucalyptus regnans forests, and (ii) average values of the global site biomass data were higher for sampled temperate moist forests (n = 44) than for sampled tropical (n = 36) and boreal (n = 52) forests (n is number of sites per forest biome). Spatially averaged Intergovernmental Panel on Climate Change biome default values are lower than our average site values for temperate moist forests, because the temperate biome contains a diversity of forest ecosystem types that support a range of mature carbon stocks or have a long land-use history with reduced carbon stocks. We describe a framework for identifying forests important for carbon storage based on the factors that account for high biomass carbon densities, including (i) relatively cool temperatures and moderately high precipitation producing rates of fast growth but slow decomposition, and (ii) older forests that are often multiaged and multilayered and have experienced minimal human disturbance. Our results are relevant to negotiations under the United Nations Framework Convention on Climate Change regarding forest conservation, management, and restoration. Conserving forests with large stocks of biomass from deforestation and degradation avoids significant carbon emissions to the atmosphere, irrespective of the source country, and should be among allowable mitigation activities. Similarly, management that allows restoration of a forest's carbon sequestration potential also should be recognized. PMID:19553199

  13. A model inter-comparison study of forest growth on two coastal and boreal forest landscapes in Canada

    NASA Astrophysics Data System (ADS)

    Bernier, P. Y.; Wang, Z.; Grant, R. F.; Arain, A.; Chen, B.; Chen, J.; Coops, N.; Govind, A.; Guindon, L.; Hember, R.; Kurz, W. A.; Peng, C.; Price, D. T.; Stinson, G.; Sun, J.; Trofymow, J. A.

    2009-05-01

    Projection of carbon stocks in Canada is presently accomplished using CBM-CFS3, an inventory-based model. We have performed a comparison exercise among 6 process-based models of forest growth (Can-IBIS, INTEC, ECOSYS, 3PG, TRIPLEX, CN-CLASS) and CBM-CFS3 as part of an effort to better capture inter-annual climate variability in the carbon accounting of Canada's forests. Comparisons were made on multi-decadal simulations for a Pacific Coastal Douglas-fir forest (2500ha, Oyster River, British Columbia) and a Boreal Black Spruce forest (3825ha, Chibougamau, Quebec). Models were initiated using reconstructions of forest composition and biomass from 1920 (Oyster River, OR) and 1928 (Chibougamau, CH), followed by transition to current forest composition as derived from recent forest inventories (OR 1999, CH 1998). Forest management events and natural disturbances over the simulation period were provided as maps and disturbance impacts on a number of carbon pools were simulated using the same transfer coefficients parameters as CBM-CFS3. Simulations were conducted from 1920 to 2006 for OR, and from 1928 to 1998 for CH. For CH, final above-ground tree biomass in 1998 was also extracted from the independent forest inventory. The coastal OR area initially contained about four times more ecosystem C than the boreal CH area. CBM- CFS3 simulations suggest a decline in ecosystem carbon by about 200 Mg C ha-1, dominated by a loss of biomass and woody debris C, over the 86-year period in OR as the entire area transitioned from coastal old- growth to second growth conditions. In CH, a smaller proportion of the area was affected by management and the CBM-CFS3 estimated a small net increase in total ecosystem C of about 11 Mg C ha-1 over 70 years, almost all attributed to increased biomass. Changes in tree biomass at CH were 10% less than estimates derived by difference between successive inventories. The source of this small simulation bias is attributable to the underlying growth

  14. Ecological, Physical, and Socioeconomic Relationships Within Southern National Forests- Proceedings of the Southern Evaluation Project Workshop

    Treesearch

    Henry A. Pearson; Fred E. Smeins; Ronald E. Thill

    1987-01-01

    The results of 43 projects, which evaluated the flora, fauna, watersheds, socioeconomics,and forest pests located on southern National Forests were presented and discussed in 4 major categories: Management Outlook and Evaluation, Loblolly-Shortleaf Pine Type, Longleaf-Slash Pine Type, and Watersheds, Socioeconomics,and Forest Pests.

  15. Capturing old-growth values for use in forest decision-making.

    PubMed

    Owen, Rochelle J; Duinker, Peter N; Beckley, Thomas M

    2009-02-01

    Old-growth forests have declined significantly across the world. Decisions related to old growth are often mired in challenges of value diversity, conflict, data gaps, and resource pressures. This article describes old-growth values of citizens and groups in Nova Scotia, Canada, for integration in sustainable forest management (SFM) decision-making. The study is based on data from 76 research subjects who participated in nine field trips to forest stands. Research subjects were drawn from Aboriginal groups, environmental organizations, forestry professionals, and rural and urban publics. Diaries, group discussions, and rating sheets were used to elicit information during the field trips. Findings show that different elicitation techniques can influence the articulation of intensity with which some values are held. In addition, certain values are more often associated with old-growth than with other forest-age classes. Some values associated with old-growth are considered more important than others, and some silvicultural treatments are perceived to compromise old-growth values more than others. Demographic characteristics, such as constituency group, gender, and age, are shown to influence value priorities. Ideas on how to incorporate old-growth values into SFM decision-making are highlighted.

  16. Influence of repeated prescribed fire on tree growth and mortality in Pinus resinosa forests, northern Minnesota

    USGS Publications Warehouse

    Bottero, Alessandra; D'Amato, Anthony W.; Palik, Brian J.; Kern, Christel C.; Bradford, John B.; Scherer, Sawyer S.

    2017-01-01

    Prescribed fire is widely used for ecological restoration and fuel reduction in fire-dependent ecosystems, most of which are also prone to drought. Despite the importance of drought in fire-adapted forests, little is known about cumulative effects of repeated prescribed burning on tree growth and related response to drought. Using dendrochronological data in red pine (Pinus resinosa Ait.)-dominated forests in northern Minnesota, USA, we examined growth responses before and after understory prescribed fires between 1960 and 1970, to assess whether repeated burning influences growth responses of overstory trees and vulnerability of overstory tree growth to drought. We found no difference in tree-level growth vulnerability to drought, expressed as growth resistance, resilience, and recovery, between areas receiving prescribed fire treatments and untreated forests. Annual mortality rates during the period of active burning were also low (less than 2%) in all treatments. These findings indicate that prescribed fire can be effectively integrated into management plans and climate change adaptation strategies for red pine forest ecosystems without significant short- or long-term negative consequences for growth or mortality rates of overstory trees.

  17. Two decades of compositional and structural change in deciduous old-growth forests of Indiana, USA

    Treesearch

    Christy A. Lowney; Bradley D. Graham; Martin A. Spetich; Stephen R. Shifley; Michael R. Saunders; Michael A. Jenkins

    2015-01-01

    AimsUsing a network of permanent plots, we determined how multiple old-growth forests changed over an 18–19-year period at a statewide scale. This examination of change allowed us to assess how the compositional and structural stability of each forest varied with site characteristics (topography, physiography and productivity)...

  18. Plot size recommendations for biomass estimation in a midwestern old-growth forest

    Treesearch

    Martin A. Spetich; George R Parker

    1998-01-01

    The authors examine the relationship between disturbance regime and plot size for woody biomass estimation in a midwestern old-growth deciduous forest from 1926 to 1992. Analysis was done on the core 19.6 ac of a 50.1 ac forest in which every tree 4 in. d.b.h. and greater has been tagged and mapped since 1926. Five windows of time are compared—1926, 1976, 1981, 1986...

  19. Distribution of biomass in an Indiana old-growth forest from 1926 to 1992

    Treesearch

    Martin A. Spetich; George R. Parker

    1998-01-01

    We examined the structural and spatial distribution of woody biomass in relationship to disturbance in an Indiana old-growth deciduous forest over a 66-year period. Analysis was done on the core 7.92 ha of a 20.6 ha forest in which every tree 10 cm dbh and over has been tagged and mapped since 1926. Five years are compared - 1926, 1976, 1981, 1986 and 1992....

  20. An Old-Growth Definition for Sand Pine Forests

    Treesearch

    Kenneth W. Outcalt

    1997-01-01

    Sand pine scrub, Society of American Foresters cover type 69 (Eyre 1980), grows on deep, droughty, infertile sands of marine and aeolian origin. Water and wind formed these features as sea levels fluctuated during past glacial and interglacial periods (Kurz 1942, Laessle 1958, Brooks 1972). Because of washing and sorting during transport and deposition, soil parent...

  1. Prediction of height increment for models of forest growth

    Treesearch

    Albert R. Stage

    1975-01-01

    Functional forms of equations were derived for predicting 10-year periodic height increment of forest trees from height, diameter, diameter increment, and habitat type. Crown ratio was considered as an additional variable for prediction, but its contribution was negligible. Coefficients of the function were estimated for 10 species of trees growing in 10 habitat types...

  2. A Novel Modelling Approach for Predicting Forest Growth and Yield under Climate Change

    PubMed Central

    Ashraf, M. Irfan; Meng, Fan-Rui; Bourque, Charles P.-A.; MacLean, David A.

    2015-01-01

    Global climate is changing due to increasing anthropogenic emissions of greenhouse gases. Forest managers need growth and yield models that can be used to predict future forest dynamics during the transition period of present-day forests under a changing climatic regime. In this study, we developed a forest growth and yield model that can be used to predict individual-tree growth under current and projected future climatic conditions. The model was constructed by integrating historical tree growth records with predictions from an ecological process-based model using neural networks. The new model predicts basal area (BA) and volume growth for individual trees in pure or mixed species forests. For model development, tree-growth data under current climatic conditions were obtained using over 3000 permanent sample plots from the Province of Nova Scotia, Canada. Data to reflect tree growth under a changing climatic regime were projected with JABOWA-3 (an ecological process-based model). Model validation with designated data produced model efficiencies of 0.82 and 0.89 in predicting individual-tree BA and volume growth. Model efficiency is a relative index of model performance, where 1 indicates an ideal fit, while values lower than zero means the predictions are no better than the average of the observations. Overall mean prediction error (BIAS) of basal area and volume growth predictions was nominal (i.e., for BA: -0.0177 cm2 5-year-1 and volume: 0.0008 m3 5-year-1). Model variability described by root mean squared error (RMSE) in basal area prediction was 40.53 cm2 5-year-1 and 0.0393 m3 5-year-1 in volume prediction. The new modelling approach has potential to reduce uncertainties in growth and yield predictions under different climate change scenarios. This novel approach provides an avenue for forest managers to generate required information for the management of forests in transitional periods of climate change. Artificial intelligence technology has substantial

  3. A Novel Modelling Approach for Predicting Forest Growth and Yield under Climate Change.

    PubMed

    Ashraf, M Irfan; Meng, Fan-Rui; Bourque, Charles P-A; MacLean, David A

    2015-01-01

    Global climate is changing due to increasing anthropogenic emissions of greenhouse gases. Forest managers need growth and yield models that can be used to predict future forest dynamics during the transition period of present-day forests under a changing climatic regime. In this study, we developed a forest growth and yield model that can be used to predict individual-tree growth under current and projected future climatic conditions. The model was constructed by integrating historical tree growth records with predictions from an ecological process-based model using neural networks. The new model predicts basal area (BA) and volume growth for individual trees in pure or mixed species forests. For model development, tree-growth data under current climatic conditions were obtained using over 3000 permanent sample plots from the Province of Nova Scotia, Canada. Data to reflect tree growth under a changing climatic regime were projected with JABOWA-3 (an ecological process-based model). Model validation with designated data produced model efficiencies of 0.82 and 0.89 in predicting individual-tree BA and volume growth. Model efficiency is a relative index of model performance, where 1 indicates an ideal fit, while values lower than zero means the predictions are no better than the average of the observations. Overall mean prediction error (BIAS) of basal area and volume growth predictions was nominal (i.e., for BA: -0.0177 cm(2) 5-year(-1) and volume: 0.0008 m(3) 5-year(-1)). Model variability described by root mean squared error (RMSE) in basal area prediction was 40.53 cm(2) 5-year(-1) and 0.0393 m(3) 5-year(-1) in volume prediction. The new modelling approach has potential to reduce uncertainties in growth and yield predictions under different climate change scenarios. This novel approach provides an avenue for forest managers to generate required information for the management of forests in transitional periods of climate change. Artificial intelligence technology

  4. Emergy and Eco-exergy Evaluation of Four Forest Restoration Modes

    EPA Science Inventory

    Four different forest restoration modes (Acacia mangium plantation, mixed-native species plantation, conifer plantation and Eucalyptus plantation) were evaluated using Energy System Theory and the emergy synthesis method. In addition, the eco-exergies of the four forest restorati...

  5. Emergy and Eco-exergy Evaluation of Four Forest Restoration Modes

    EPA Science Inventory

    Four different forest restoration modes (Acacia mangium plantation, mixed-native species plantation, conifer plantation and Eucalyptus plantation) were evaluated using Energy System Theory and the emergy synthesis method. In addition, the eco-exergies of the four forest restorati...

  6. Tree species and soil nutrient profiles in old-growth forests of the Oregon Coast Range

    USGS Publications Warehouse

    Cross, Alison; Perakis, Steven S.

    2011-01-01

    Old-growth forests of the Pacific Northwest provide a unique opportunity to examine tree species – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy tree species (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most species-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four tree species that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.

  7. Evaluating the suitability of management strategies of pure Norway spruce forests in the Black Forest area of southwest Germany for adaptation to or mitigation of climate change.

    PubMed

    Yousefpour, Rasoul; Hanewinkel, Marc; Le Moguédec, Gilles

    2010-02-01

    The study deals with the problem of evaluating management strategies for pure stands of Norway spruce (Picea abies Karst) to balance adaptation to and mitigation of climate change, taking into account multiple objectives of a forest owner. A simulation and optimization approach was used to evaluate the management of a 1000 ha model Age-Class forest, representing the age-class distribution of an area of 66,000 ha of pure Norway spruce forests in the Black Forest region of Southwest Germany. Eight silvicultural scenarios comprising five forest conversion schemes which were interpreted as "adaptation" strategies which aims at increasing the proportion of Beech, that is expected to better cope with climate change than the existing Norway spruce, and three conventional strategies including a "Do-nothing" alternative classified as "mitigation", trying to keep rather higher levels of growing stock of spruce, were simulated using the empirical growth simulator BWINPro-S. A linear programming approach was adapted to simultaneously maximize the net present values of carbon sequestration and timber production subject to the two constraints of wood even flow and partial protection of the oldest (nature protection). The optimized plan, with the global utility of 11,687 /ha in forty years, allocated a combination of silvicultural scenarios to the entire forest area. Overall, strategies classified as "mitigation" were favored, while strategies falling into the "adaptation"-category were limited to the youngest age-classes in the optimal solution. Carbon sequestration of the "Do-nothing" alternative was between 1.72 and 1.85 million tons higher than the other alternatives for the entire forest area while the differences between the adaptation and mitigation approaches were approximately 133,000 tons. Sensitivity analysis showed that a carbon price of 21 /t is the threshold at which carbon sequestration is promoted, while an interest rate of above 2% would decrease the

  8. Evaluating the Suitability of Management Strategies of Pure Norway Spruce Forests in the Black Forest Area of Southwest Germany for Adaptation to or Mitigation of Climate Change

    NASA Astrophysics Data System (ADS)

    Yousefpour, Rasoul; Hanewinkel, Marc; Le Moguédec, Gilles

    2010-02-01

    The study deals with the problem of evaluating management strategies for pure stands of Norway spruce ( Picea abies Karst) to balance adaptation to and mitigation of climate change, taking into account multiple objectives of a forest owner. A simulation and optimization approach was used to evaluate the management of a 1000 ha model Age-Class forest, representing the age-class distribution of an area of 66,000 ha of pure Norway spruce forests in the Black Forest region of Southwest Germany. Eight silvicultural scenarios comprising five forest conversion schemes which were interpreted as “adaptation” strategies which aims at increasing the proportion of Beech, that is expected to better cope with climate change than the existing Norway spruce, and three conventional strategies including a “Do-nothing” alternative classified as “mitigation”, trying to keep rather higher levels of growing stock of spruce, were simulated using the empirical growth simulator BWINPro-S. A linear programming approach was adapted to simultaneously maximize the net present values of carbon sequestration and timber production subject to the two constraints of wood even flow and partial protection of the oldest (nature protection). The optimized plan, with the global utility of 11,687 €/ha in forty years, allocated a combination of silvicultural scenarios to the entire forest area. Overall, strategies classified as “mitigation” were favored, while strategies falling into the “adaptation”-category were limited to the youngest age-classes in the optimal solution. Carbon sequestration of the “Do-nothing” alternative was between 1.72 and 1.85 million tons higher than the other alternatives for the entire forest area while the differences between the adaptation and mitigation approaches were approximately 133,000 tons. Sensitivity analysis showed that a carbon price of 21 €/ t is the threshold at which carbon sequestration is promoted, while an interest rate of above 2

  9. Evaluation of single-nucleotide polymorphism imputation using random forests

    PubMed Central

    2009-01-01

    Genome-wide association studies (GWAS) have helped to reveal genetic mechanisms of complex diseases. Although commonly used genotyping technology enables us to determine up to a million single-nucleotide polymorphisms (SNPs), causative variants are typically not genotyped directly. A favored approach to increase the power of genome-wide association studies is to impute the untyped SNPs using more complete genotype data of a reference population. Random forests (RF) provides an internal method for replacing missing genotypes. A forest of classification trees is used to determine similarities of probands regarding their genotypes. These proximities are then used to impute genotypes of untyped SNPs. We evaluated this approach using genotype data of the Framingham Heart Study provided as Problem 2 for Genetic Analysis Workshop 16 and the Caucasian HapMap samples as reference population. Our results indicate that RFs are faster but less accurate than alternative approaches for imputing untyped SNPs. PMID:20018059

  10. Evaluating Landsat classification accuracy from forest cover-type maps

    NASA Technical Reports Server (NTRS)

    Hudson, W. D.

    1987-01-01

    The use of complete enumeration in the form of photointerpreted forest cover-type maps to evaluate the accuracy of Landsat classifications was compared with assessments made directly from the aerial photography. A computerized, geographic information system was utilized to compare the Landsat classifications with the cover-type maps on a pixel-by-pixel basis. Error maps of pixels which were similarly misclassified by a variety of algorithms contained a larger number of errors than were verified from the aerial photography. For the two test sites studied, only 67 and 52 percent of the pixels which were originally considered to be in error were substantiated as being in error. Discrepancies between the two results were primarily caused by definitional differences between the cover-type maps and the Landsat classifications, especially with regard to minimum-type size and crown closure estimates of forest land.

  11. Evaluation of forest thinning materials for TMP production

    Treesearch

    John H. Klungness; Roland Gleisner; Doreen Mann; Karen L. Scallon; J.Y. Zhu; Eric G. Horn; Louis L. Edwards

    2005-01-01

    We used SilviScan analysis and tracheid measurement to evaluate the effect of suppressed growth on the fundamental properties of wood fiber. Suppressed growth reduced cell tracheid length, but the high content of mature wood may translate into longer fibers overall. In pilot-scale refining experiments, blending 25% chips from small-diameter trees (SMD) with 75% mill...

  12. Evaluation of postnatal growth of preterm infants.

    PubMed

    Bertino, Enrico; Di Nicola, Paola; Giuliani, Francesca; Coscia, Alessandra; Varalda, Alessia; Occhi, Luciana; Rossi, Claudia

    2011-10-01

    The past two decades have seen a progressive improvement in the survival rates of preterm infants, especially in neonates <30 weeks of gestational age. These neonates constitute the large majority of the population in neonatal intensive care units. The correct evaluation of postnatal growth of these babies is nowadays of primary concern, although the definition of their optimal postnatal growth pattern is still controversial. Concerns have also been raised about the strategies to monitor their growth, specifically in relation to the charts used. At present the available charts in clinical practice are fetal growth charts, neonatal anthropometric charts and postnatal growth charts for term infants. None of these, for different reasons, is suitable to correctly evaluate preterm infant growth. An international multicentric project has recently started a study aiming at building a prescriptive standard for the evaluation of postnatal growth of preterm infants and it will be available in the next years providing a population that is conceptually as close as possible to the prescriptive approach used for the construction of the WHO infant and child growth standards. At present, while an international longitudinal standard for evaluating preterm infant postnatal growth is lacking, in Italy the best compromise in clinical practice is likely to be as follows: new Italian INeS (Italian Neonatal Study) charts up to term; International longitudinal charts WHO 2006 or CDC 2002 from term to two years; finally the Italian Society for Pediatric Endocrinology and Diabetes (SIEDP) 2006 growth charts could be suitable for monitoring the growth of these infants from two years up to 20 years of age.

  13. Composition, structure, and dendroecology of an old-growth Quercus forest on the tablelands of the Cumberland Plateau, USA.

    Treesearch

    Justin L. Hart; Stacy L. Clark; Scott J. Torreano; Megan L. Buchanan

    2011-01-01

    Forest reconstructions provide information on the processes that influence forest development and successional patterns. In this study, we quantified woody species composition, stand structure, and radial growth patterns of individual Quercus trees to document the processes that shaped a forest on the Cumberland Plateau in Tennessee over the past three centuries. The...

  14. Upland log volumes and conifer establishment patterns in two northern, upland old-growth redwood forests, a brief synopsis

    Treesearch

    Daniel J. Porter; John O. Sawyer

    2007-01-01

    We characterized the volume, weight and top surface area of naturally fallen logs in an old-growth redwood forest, and quantified conifer recruit densities on these logs and on the surrounding forest floor. We report significantly greater conifer recruit densities on log substrates as compared to the forest floor. Log substrate availability was calculated on a per...

  15. Chapter 20: geographic variability in growth of forest trees

    Treesearch

    Robert Z. Callaham

    1962-01-01

    Tree growth, like all plant characters, is a product of the interaction of genes and environment; however, the genes, environment, and interaction are not the same for every individual of a species. Genes exert master control over the plant's growth mechanisms. They control mechanisms for responding to environment and for utilizing environment in growth. Usually...

  16. Regionally averaged diameter growth in New England forests

    Treesearch

    Robert B. Smith; James W. Hornbeck; C. Anthony Federer; Paul J., Jr. Krusic; Paul J. Krusic

    1990-01-01

    A regional sample of tree-ring measurements was used to determine average annual growth in trees of 10 major species in New England. There have been extended periods of decreasing growth rates in red spruce since about 1960 and in balsam fir since about 1965. The other eight species, which included sugar maple and white pine, showed constant or increasing growth rates...

  17. The linkages between photosynthesis, productivity, growth and biomass in lowland Amazonian forests.

    PubMed

    Malhi, Yadvinder; Doughty, Christopher E; Goldsmith, Gregory R; Metcalfe, Daniel B; Girardin, Cécile A J; Marthews, Toby R; Del Aguila-Pasquel, Jhon; Aragão, Luiz E O C; Araujo-Murakami, Alejandro; Brando, Paulo; da Costa, Antonio C L; Silva-Espejo, Javier E; Farfán Amézquita, Filio; Galbraith, David R; Quesada, Carlos A; Rocha, Wanderley; Salinas-Revilla, Norma; Silvério, Divino; Meir, Patrick; Phillips, Oliver L

    2015-06-01

    Understanding the relationship between photosynthesis, net primary productivity and growth in forest ecosystems is key to understanding how these ecosystems will respond to global anthropogenic change, yet the linkages among these components are rarely explored in detail. We provide the first comprehensive description of the productivity, respiration and carbon allocation of contrasting lowland Amazonian forests spanning gradients in seasonal water deficit and soil fertility. Using the largest data set assembled to date, ten sites in three countries all studied with a standardized methodology, we find that (i) gross primary productivity (GPP) has a simple relationship with seasonal water deficit, but that (ii) site-to-site variations in GPP have little power in explaining site-to-site spatial variations in net primary productivity (NPP) or growth because of concomitant changes in carbon use efficiency (CUE), and conversely, the woody growth rate of a tropical forest is a very poor proxy for its productivity. Moreover, (iii) spatial patterns of biomass are much more driven by patterns of residence times (i.e. tree mortality rates) than by spatial variation in productivity or tree growth. Current theory and models of tropical forest carbon cycling under projected scenarios of global atmospheric change can benefit from advancing beyond a focus on GPP. By improving our understanding of poorly understood processes such as CUE, NPP allocation and biomass turnover times, we can provide more complete and mechanistic approaches to linking climate and tropical forest carbon cycling.

  18. Spatial climate-dependent growth response of boreal mixedwood forest in western Canada

    NASA Astrophysics Data System (ADS)

    Jiang, Xinyu; Huang, Jian-Guo; Stadt, Kenneth J.; Comeau, Philip G.; Chen, Han Y. H.

    2016-04-01

    The western Canadian mixedwood boreal forests were projected to be significantly affected by regional drought. However, drought degrees were spatially different across elevations, longitudes and latitudes, which might cause different tree growth responses to climate change in different sub-regions within western Canada. In this way, regional classification of western Canadian boreal forests and understanding spatial tree growth responses to climate might be necessary for future forest management and monitoring. In this paper, tree-ring chronologies of two dominant tree species, trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench.) Voss), were obtained from mixed forest stands distributed across western Canada to study spatial tree growth response to climate based on three regional classification schemes (a phytogeographic sub-region classification, a natural sub-region classification and non-classification). Phytogeographic sub-region classification was estimated based on tree ring samples we collected in this study, while natural sub-region classification was previously developed based on analysis of regional differences in vegetation, soil, site and climate conditions. Results showed that air temperature did not significantly increase, while drought stress became more severe between 1985 to 2010. Relationships between trembling aspen growth and temperature differed between north and south parts of the study area, resulting from spatial difference in water supply. Trembling aspen growth was influenced by temperature or moisture variables of the previous years. White spruce growth was influenced primarily by moisture variables (current or previous year), and response coefficients between white spruce and drought conditions (represented by drought code) were negative in all phytogeographic sub-regions, suggesting that white spruce was more sensitive to drought stress under climate change. As a late-successional dominant species

  19. Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics.

    PubMed

    Chazdon, Robin L; Broadbent, Eben N; Rozendaal, Danaë M A; Bongers, Frans; Zambrano, Angélica María Almeyda; Aide, T Mitchell; Balvanera, Patricia; Becknell, Justin M; Boukili, Vanessa; Brancalion, Pedro H S; Craven, Dylan; Almeida-Cortez, Jarcilene S; Cabral, George A L; de Jong, Ben; Denslow, Julie S; Dent, Daisy H; DeWalt, Saara J; Dupuy, Juan M; Durán, Sandra M; Espírito-Santo, Mario M; Fandino, María C; César, Ricardo G; Hall, Jefferson S; Hernández-Stefanoni, José Luis; Jakovac, Catarina C; Junqueira, André B; Kennard, Deborah; Letcher, Susan G; Lohbeck, Madelon; Martínez-Ramos, Miguel; Massoca, Paulo; Meave, Jorge A; Mesquita, Rita; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Nunes, Yule R F; Ochoa-Gaona, Susana; Orihuela-Belmonte, Edith; Peña-Claros, Marielos; Pérez-García, Eduardo A; Piotto, Daniel; Powers, Jennifer S; Rodríguez-Velazquez, Jorge; Romero-Pérez, Isabel Eunice; Ruíz, Jorge; Saldarriaga, Juan G; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B; Steininger, Marc K; Swenson, Nathan G; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria D M; Vester, Hans; Vieira, Ima Celia G; Bentos, Tony Vizcarra; Williamson, G Bruce; Poorter, Lourens

    2016-05-01

    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km(2) of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from 1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forest management, natural regeneration of second-growth forests provides a low-cost mechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services.

  20. Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics

    PubMed Central

    Chazdon, Robin L.; Broadbent, Eben N.; Rozendaal, Danaë M. A.; Bongers, Frans; Zambrano, Angélica María Almeyda; Aide, T. Mitchell; Balvanera, Patricia; Becknell, Justin M.; Boukili, Vanessa; Brancalion, Pedro H. S.; Craven, Dylan; Almeida-Cortez, Jarcilene S.; Cabral, George A. L.; de Jong, Ben; Denslow, Julie S.; Dent, Daisy H.; DeWalt, Saara J.; Dupuy, Juan M.; Durán, Sandra M.; Espírito-Santo, Mario M.; Fandino, María C.; César, Ricardo G.; Hall, Jefferson S.; Hernández-Stefanoni, José Luis; Jakovac, Catarina C.; Junqueira, André B.; Kennard, Deborah; Letcher, Susan G.; Lohbeck, Madelon; Martínez-Ramos, Miguel; Massoca, Paulo; Meave, Jorge A.; Mesquita, Rita; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Nunes, Yule R. F.; Ochoa-Gaona, Susana; Orihuela-Belmonte, Edith; Peña-Claros, Marielos; Pérez-García, Eduardo A.; Piotto, Daniel; Powers, Jennifer S.; Rodríguez-Velazquez, Jorge; Romero-Pérez, Isabel Eunice; Ruíz, Jorge; Saldarriaga, Juan G.; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B.; Steininger, Marc K.; Swenson, Nathan G.; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria D. M.; Vester, Hans; Vieira, Ima Celia G.; Bentos, Tony Vizcarra; Williamson, G. Bruce; Poorter, Lourens

    2016-01-01

    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km2 of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from 1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forest management, natural regeneration of second-growth forests provides a low-cost mechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services. PMID:27386528

  1. Forest growth and timber quality: crown models and simulation methods for sustainable forest management

    Treesearch

    Dennis P. Dykstra; Robert A. Monserud

    2009-01-01

    The purpose of the international conference from which these proceedings are drawn was to explore relationships between forest management activities and timber quality. Sessions were organized to explore models and simulation methodologies that contribute to an understanding of tree development over time and the ways that management and harvesting activities can...

  2. Considerations in Forest Growth Estimation Between Two Measurements of Mapped Forest Inventory Plots

    Treesearch

    Michael T. Thompson

    2006-01-01

    Several aspects of the enhanced Forest Inventory and Analysis (FIA) program?s national plot design complicate change estimation. The design incorporates up to three separate plot sizes (microplot, subplot, and macroplot) to sample trees of different sizes. Because multiple plot sizes are involved, change estimators designed for polyareal plot sampling, such as those...

  3. Integrating forest growth and harvesting cost models to improve forest management planning

    Treesearch

    J.E. Baumgras; C.B. LeDoux

    1991-01-01

    Two methods of estimating harvesting revenue--reported stumpage prices - and delivered prices minus estimated harvesting and haul costs were compared by estimating entry cash flows and rotation net present value for three simulated even-aged forest management options that included 1 to 3 thinnings over a 90 year rotation. Revenue estimates derived from stumpage prices...

  4. Dampening effects of long-term experimental drought on growth and mortality rates of a Holm oak forest.

    PubMed

    Barbeta, Adrià; Ogaya, Romà; Peñuelas, Josep

    2013-10-01

    evaluate the effect of long-term (13 years) experimental drought on growth and mortality rates of three forest Mediterranean species, and their response to the different intensities and durations of natural drought. We provide evidence for species-specific responses to drought, what may eventually lead to a partial community shift favoring the more drought-resistant species. However, we also report a dampening of the treatment effect on the two drought-sensitive species, which may indicate a potential adaptation to drier conditions at the ecosystem or population level. These results are thus relevant to account for the stabilizing processes that would alter the initial response of ecosystem to drought through changes in plant physiology, morphology, and demography compensation. © 2013 John Wiley & Sons Ltd.

  5. Forest Tree Growth as a Bioindicator of Pollution Abatement Systems at the Radford Army Ammunition Plant.

    DTIC Science & Technology

    1982-01-14

    U-0Al C 0LIGNAPLTCGICIS P TT IY BLCSUG-EC FS1/ FOREST TREE GROWTH AS A BIOINDICATOR OF POLLUTION ABATEMENT SYS--ETC(I 𔃾- oa2 JAN 62 J M SKELLY. L W...947! FOREST TREE GROWTH AS A BIOINDICATOR OF POLLUTION ABATEMENT SYSTEMS AT THE RADFORD ARMY AMMUNITION PLANT Accession For FINAL REPORT Dr. John M...test potential bioindicator systems. x The study objectives of this research were: i’l) To determine if the pollution levels alone were responsible

  6. Chronic water stress reduces tree growth and the carbon sink of deciduous hardwood forests.

    PubMed

    Brzostek, Edward R; Dragoni, Danilo; Schmid, Hans Peter; Rahman, Abdullah F; Sims, Daniel; Wayson, Craig A; Johnson, Daniel J; Phillips, Richard P

    2014-08-01

    Predicted decreases in water availability across the temperate forest biome have the potential to offset gains in carbon (C) uptake from phenology trends, rising atmospheric CO2 , and nitrogen deposition. While it is well established that severe droughts reduce the C sink of forests by inducing tree mortality, the impacts of mild but chronic water stress on forest phenology and physiology are largely unknown. We quantified the C consequences of chronic water stress using a 13-year record of tree growth (n = 200 trees), soil moisture, and ecosystem C balance at the Morgan-Monroe State Forest (MMSF) in Indiana, and a regional 11-year record of tree growth (n > 300 000 trees) and water availability for the 20 most dominant deciduous broadleaf tree species across the eastern and midwestern USA. We show that despite ~26 more days of C assimilation by trees at the MMSF, increasing water stress decreased the number of days of wood production by ~42 days over the same period, reducing the annual accrual of C in woody biomass by 41%. Across the deciduous forest region, water stress induced similar declines in tree growth, particularly for water-demanding 'mesophytic' tree species. Given the current replacement of water-stress adapted 'xerophytic' tree species by mesophytic tree species, we estimate that chronic water stress has the potential to decrease the C sink of deciduous forests by up to 17% (0.04 Pg C yr(-1) ) in the coming decades. This reduction in the C sink due to mesophication and chronic water stress is equivalent to an additional 1-3 days of global C emissions from fossil fuel burning each year. Collectively, our results indicate that regional declines in water availability may offset the growth-enhancing effects of other global changes and reduce the extent to which forests ameliorate climate warming. © 2014 John Wiley & Sons Ltd.

  7. A diameter growth model for single-stem growth forms for the interior west forest inventory and analysis’s region

    Treesearch

    Michael T. Thompson

    2015-01-01

    The Interior West Forest Inventory and Analysis Unit (IWFIA) will soon transition from a regional system to a national FIA system for compiling estimates of forest growth, removals, and mortality. The national system requires regional diameter-growth models to estimate diameters on trees in situations where the initial or terminal diameter is not known at the beginning...

  8. Implementing a national process for estimating growth, removals, and mortality at the Pacific Northwest’s Forest Inventory and Analysis’s Region: modeling diameter growth

    Treesearch

    Olaf. Kuegler

    2015-01-01

    The Pacific Northwest Research Station’s Forest Inventory and Analysis Unit began remeasurement of permanently located FIA plots under the annualized design in 2011. With remeasurement has come the need to implement the national FIA system for compiling estimates of forest growth, removals, and mortality. The national system requires regional diameter-growth models to...

  9. Protecting rare, old-growth, forest-associated species under the Survey and Manage program guidelines of the northwest forest plan.

    Treesearch

    Randy Molina; Bruce G. Marcot; Robin. Lesher

    2006-01-01

    The Survey and Manage Program of the Northwest Forest Plan (MFP) represents an unparalleled attempt to protect rare, little-known species associated with late-successional and old-growth forests on more than 7.7 million ha of federal lands. Approximately 400 species of amphibians, bryophytes, fungi, lichens, mollusks, vascular plants, arthropod functional groups, and...

  10. Succession-inducing disturbances and the old-growth forest mosaic of a Central Amazon landscape

    NASA Astrophysics Data System (ADS)

    Chambers, J. Q.; Negron Juarez, R. I.; Marra, D.; Roberts, D. A.; Di Vittorio, A. V.; Higuchi, N.; Trumbore, S.

    2011-12-01

    Old-growth forest ecosystems comprise a mosaic of patches in different successional stages, with the fraction of the landscape in any particular state relatively constant over large temporal and spatial scales. Tropical forest studies commonly assume that plots covering only a small fraction of the landscape representatively sample this mosaic, and that departures from steady-state represent trends. Here a critical test of this equilibrium assumption for a Central Amazon old-growth forest landscape is carried out by combining extensive forest field plot data, remote sensing analysis to generate disturbance probability distribution functions, and simulation modeling to place plot-level results into a landscape context. Results show that succession-inducing disturbances had a return frequency of ~100 years, and that these episodic events have been poorly sampled by existing forest sample plots. Overall, key ecosystem attributes of small patches are expected to constantly change in the Central Amazon, and long significant trends can result from purely stochastic processes. The role of episodic disturbances will be discussed in terms of Amazon forest carbon balance, and regional tree diversity patterns.

  11. The dynamics of annual carbon allocation to wood in European forests is consistent with a combined source-sink limitation of growth.

    NASA Astrophysics Data System (ADS)

    Guillemot, Joannès; Martin-StPaul, Nicolas K.; Dufrêne, Eric; François, Christophe; Soudani, Kamel; Ourcival, Jean-Marc; Leadley, Paul; Delpierre, Nicolas

    2015-04-01

    The extent to which forest growth is limited by carbon (C) supply (source control) or by cambial activity (sink control) will strongly determines the responses of trees to global changes. However, the physiological processes responsible for the limitation of forest growth are still under debate. The aim of this study was i) to evaluate the key drivers of the annual carbon allocation to wood along large soil and climate regional gradients in four tree species representative of the main European forest biomes (Fagus sylvatica, Quercus petraea, Quercus ilex and Picea abies) ii) to implement the identified key drivers in a new C allocation scheme within the CASTANEA terrestrial biosphere model (TBM). Combining field measurements and process-based simulations at 49 sites (931 site-years), our analyses revealed that the inter-site variability in C allocation to wood was predominantly driven by an age-related decline. The direct control of temperature or water stress on sink activity (i.e. independently from their effects on C supply) exerted a strong influence on the annual woody growth in all the species considered, including deciduous temperate species. The lagged effect of the past environment conditions was a significant driver of the annual C allocation to wood. Carbon supply appeared to strongly limit growth only in deciduous temperate species. Our study supports the premise that European forest growth is under a complex panel of source- and sink- limitations, contradicting the simple source control implemented in most TBMs. The implementation of these combined forest growth limitations in the CASTANEA model significantly improved its performance when evaluated against independent stand growth data at the regional scale (mainland France, >10000 plots). We finally discuss how the sink imitation affects the CASTANEA simulated projections of forest productivity along the 21th century, especially with respect to the expected fertilizing effect of increasing atmospheric

  12. Spatial and temporal variation in soil CO2 efflux in an old-growth neotropical rain forest, LA Selva, Costa Rica

    Treesearch

    Luitgard Schwendenmann; Edzo Veldkamp; Tania Brenes; Joseph J. O' Brien; Jens Mackensen

    2003-01-01

    Our objectives were to quantify and compare soil CO2, efflux of two doininant soil types in an old-growth neotropical rain forest in the Atlantic zone of Costa Rica, and to evaluate the control of environmental Factors on CO2, release. We measured soil CO2 efflux from eight permanent soil chamhers on...

  13. Tree growth variation in the tropical forest: understanding effects of temperature, rainfall and CO2.

    PubMed

    Schippers, Peter; Sterck, Frank; Vlam, Mart; Zuidema, Pieter A

    2015-01-28

    Tropical forest responses to climatic variability have important consequences for global carbon cycling, but are poorly understood. As empirical, correlative studies cannot disentangle the interactive effects of climatic variables on tree growth, we used a tree growth model (IBTREE) to unravel the climate effects on different physiological pathways and in turn on stem growth variation. We parameterized the model for canopy trees of Toona ciliata (Meliaceae) from a Thai monsoon forest and compared predicted and measured variation from a tree-ring study over a 30-year period. We used historical climatic variation of minimum and maximum day temperature, precipitation and carbon dioxide (CO2 ) in different combinations to estimate the contribution of each climate factor in explaining the inter-annual variation in stem growth. Running the model with only variation in maximum temperature and rainfall yielded stem growth patterns that explained almost 70% of the observed inter-annual variation in stem growth. Our results show that maximum temperature had a strong negative effect on the stem growth by increasing respiration, reducing stomatal conductance and thus mitigating a higher transpiration demand, and - to a lesser extent - by directly reducing photosynthesis. Although stem growth was rather weakly sensitive to rain, stem growth variation responded strongly and positively to rainfall variation owing to the strong inter-annual fluctuations in rainfall. Minimum temperature and atmospheric CO2 concentration did not significantly contribute to explaining the inter-annual variation in stem growth. Our innovative approach - combining a simulation model with historical data on tree-ring growth and climate - allowed disentangling the effects of strongly correlated climate variables on growth through different physiological pathways. Similar studies on different species and in different forest types are needed to further improve our understanding of the sensitivity of

  14. Allocation trade-offs dominate the response of tropical forest growth to seasonal and interannual drought.

    PubMed

    Doughty, Christopher E; Malhi, Yadvinder; Araujo-Murakami, Alejandro; Metcalfe, Daniel B; Silva-Espejo, Javier E; Arroyo, Luzmila; Heredia, Juan P; Pardo-Toledo, Erwin; Mendizabal, Luz M; Rojas-Landivar, Victor D; Vega-Martinez, Meison; Flores-Valencia, Marcio; Sibler-Rivero, Rebeca; Moreno-Vare, Luzmarina; Viscarra, Laura Jessica; Chuviru-Castro, Tamara; Osinaga-Becerra, Marilin; Ledezma, Roxana

    2014-08-01

    What determines the seasonal and interannual variation of growth rates in trees in a tropical forest? We explore this question with a novel four-year high-temporal-resolution data set of carbon allocation from two forest plots in the Bolivian Amazon. The forests show strong seasonal variation in tree wood growth rates, which are largely explained by shifts in carbon allocation, and not by shifts in total productivity. At the deeper soil plot, there was a clear seasonal trade-off between wood and canopy NPP, while the shallower soils plot showed a contrasting seasonal trade-off between wood and fine roots. Although a strong 2010 drought reduced photosynthesis, NPP remained constant and increased in the six-month period following the drought, which indicates usage of significant nonstructural carbohydrate stores. Following the drought, carbon allocation increased initially towards the canopy, and then in the following year, allocation increased towards fine-root production. Had we only measured woody growth at these sites and inferred total NPP, we would have misinterpreted both the seasonal and interannual responses. In many tropical forest ecosystems, we propose that changing tree growth rates are more likely to reflect shifts in allocation rather than changes in overall productivity. Only a whole NPP allocation perspective can correctly interpret the relationship between changes in growth and changes in productivity.

  15. The influence of sampling design on tree-ring-based quantification of forest growth.

    PubMed

    Nehrbass-Ahles, Christoph; Babst, Flurin; Klesse, Stefan; Nötzli, Magdalena; Bouriaud, Olivier; Neukom, Raphael; Dobbertin, Matthias; Frank, David

    2014-09-01

    Tree-rings offer one of the few possibilities to empirically quantify and reconstruct forest growth dynamics over years to millennia. Contemporaneously with the growing scientific community employing tree-ring parameters, recent research has suggested that commonly applied sampling designs (i.e. how and which trees are selected for dendrochronological sampling) may introduce considerable biases in quantifications of forest responses to environmental change. To date, a systematic assessment of the consequences of sampling design on dendroecological and-climatological conclusions has not yet been performed. Here, we investigate potential biases by sampling a large population of trees and replicating diverse sampling designs. This is achieved by retroactively subsetting the population and specifically testing for biases emerging for climate reconstruction, growth response to climate variability, long-term growth trends, and quantification of forest productivity. We find that commonly applied sampling designs can impart systematic biases of varying magnitude to any type of tree-ring-based investigations, independent of the total number of samples considered. Quantifications of forest growth and productivity are particularly susceptible to biases, whereas growth responses to short-term climate variability are less affected by the choice of sampling design. The world's most frequently applied sampling design, focusing on dominant trees only, can bias absolute growth rates by up to 459% and trends in excess of 200%. Our findings challenge paradigms, where a subset of samples is typically considered to be representative for the entire population. The only two sampling strategies meeting the requirements for all types of investigations are the (i) sampling of all individuals within a fixed area; and (ii) fully randomized selection of trees. This result advertises the consistent implementation of a widely applicable sampling design to simultaneously reduce uncertainties in

  16. Forest disturbance spurs growth of modeling and technology

    NASA Astrophysics Data System (ADS)

    Bohrer, G.; Matheny, A. M.; Mirfenderesgi, G.; Morin, T. H.; Rey Sanchez, A. C.; Gough, C. M.; Vogel, C. S.; Nadelhoffer, K. J.; Curtis, P.

    2016-12-01

    As new opportunities for scientific exploration open, needs for data generate a drive for innovative developments of new research tools. The Forest Accelerated Succession ExperimenT (FASET) was enacted in 2007, continuous flux observations at the University of Michigan Biological Station (UMBS) since 2000. FASET is a large-scale ecological experiment testing the immediate and intermediate term effects of disturbance, and eventually, the role of succession and community composition on forest flux dynamics. Decades-long tree-level observations in the UMBS forest, combined with the long term flux observations allowed us to match the bottom-up accumulated response of individual trees with the top-down whole-plot response measured from the flux tower. However, data describing tree-level canopy structure and hydrological response over an entire plot were not readily available. Unintentionally, FASET became both a motivation and a test-bed for new research tools and approaches. We expanded the operation and analysis approach for a portable canopy LiDARfor 3-D measurements meter-scale canopy structure. We matched canopy LiDAR measurements with root measurements from ground penetrating radar. To study the hydrological effects of the disturbance, we instrumented a large number of trees with Granier-style sap flux sensors. We further developed an approach to use frequency domain reflectometry sensors for continuous measurements of tree water content. We developed an approach to combine plot census, allometry and sap-flux observations in a bottom-up fashion to compare with plot-level EC transpiration rates. We found that while the transpirational water demand in the disturbance plot increased, overall evapotranspiration decreased. This decrease, however, is not uniform across species. A new individual-plant to ecosystem scale hydrodynamic model (FETCH2) demonstrates how specific traits translate to intra-daily differences in plot-level transpiration dynamics.

  17. Regional Rates of Young US Forest Growth Estimated From Annual Landsat Disturbance History and IKONOS Stereo Imagery

    NASA Technical Reports Server (NTRS)

    Neigh, Christopher S. R.; Masek, Jeffrey G.; Bourget, Paul; Rishmawi, Khaldoun; Zhao, Feng; Huang, Chengquan; Cook, Bruce D.; Nelson, Ross

    2015-01-01

    Forests of the Contiguous United States (CONUS) have been found to be a large contributor to the global atmospheric carbon sink. The magnitude and nature of this sink is still uncertain and recent studies have sought to define the dynamics that control its strength and longevity. The Landsat series of satellites has been a vital resource to understand the long-term changes in land cover that can impact ecosystem function and terrestrial carbonstock. We combine annual Landsat forest disturbance history from 1985 to 2011 with single date IKONOS stereoimagery to estimate the change in young forest canopy height and above ground live dry biomass accumulation for selected sites in the CONUS. Our approach follows an approximately linear growth rate following clearing over short intervals and does not estimate the distinct non-linear growth rate over longer intervals.We produced canopy height models by differencing digital surface models estimated from IKONOS stereo pairs with national elevation data (NED). Correlations between height and biomass were established independently using airborne LiDAR, and then applied to the IKONOS-estimated canopy height models. Graphing current biomass against time since disturbance provided biomass accumulation rates. For 20 study sites distributed across five regions of the CONUS, 19 showed statistically significant recovery trends (p is less than 0.001) with canopy growth from 0.26 m yr-1to 0.73 m yr-1. Above ground live dry biomass (AGB) density accumulation ranged from 1.31 t/ha yr-1 to 12.47 t/ha yr-1. Mean forest AGB accumulationwas 6.31 t/ha yr-1 among all sites with significant growth trends. We evaluated the accuracy of our estimates by comparing to field estimated site index curves of growth, airborne LiDAR data, and independent model predictions of C accumulation. Growth estimates found with this approach are consistent with site index curves and total biomass estimates fall within the range of field estimates. This is aviable

  18. Impacts of urban growth on forest cover in Istanbul (1987-2007).

    PubMed

    Karaburun, Ahmet; Demirci, Ali; Suen, I-Shian

    2010-07-01

    This article reports findings of a study that examined the impacts of urban growth on forest cover in Istanbul between 1987 and 2007. Four Landsat images from 1987, 1990, 2000, and 2007 were classified with maximum likelihood supervised classification method by using ERDAS IMAGINE 9.1. Forest and urban areas were given highest importance in the classification, while other land-use characteristics, like agriculture and bare soil, were grouped into a third class as others. The study revealed that rapid increase in population and accompanying unplanned urban growth in Istanbul resulted in significant changes in land use after 1987. Urban areas have expanded 87.9% from 1987 to 2007, while forest areas declined 5.4% in the same period. One of the most significant results of the study was that total forest areas in Istanbul have increased 0.3% between 2000 and 2007. This suggests that progress has been made in Istanbul not only in having sustainable urban growth, but also in preserving, restoring, and even expanding forest areas, especially after the year 2000.

  19. A volume change index for forest growth and sustainability

    Treesearch

    Paul Van Deusen; Francis Roesch

    2009-01-01

    A volume change index is suggested that is derived from growth components that can be estimated from remeasured plots. The new index incorporates more information than the traditional growth over removals, ratio. The new index directly indicates whether the standing volume will be increasing or decreasing if current conditions persist, whereas the ratio of...

  20. Soil acidification by atmospheric pollution and forest growth

    Treesearch

    Bengt Jonsson

    1976-01-01

    In recent years concern has been expressed about the danger of harmful pollution deposits which affect areas at great distances from the emission sources. The investigation was so designed that a possible reaction in growth resulting from a supposed acidification could be observed as far as possible. A poorer growth development was observed in regions, which are...

  1. Forest Growth and Yield Models Viewed From a Different Perspective

    Treesearch

    Jeffery C. Goelz

    2002-01-01

    Typically, when different forms of growth and yield models are considered, they are grouped into convenient discrete classes. As a heuristic device, I chose to use a contrasting perspective, that all growth and yield models are diameter distribution models that merely differ in regard to which diameter distribution is employed and how the distribution is projected to...

  2. Housing growth, forests, and public lands in Northern Wisconsin from 1940 to 2000.

    PubMed

    Hammer, Roger B; Stewart, Susan I; Hawbaker, Todd J; Radeloff, Volker C

    2009-06-01

    Rural, forested areas throughout the United States are experiencing strong housing growth with potentially detrimental impacts on the environment. In this paper, we quantify housing growth in Northern Wisconsin over the last sixty years to determine if growth rates were higher near public lands, which may represent an important recreational amenity. We used data from the U.S. Census to produce decadal housing density estimates, "backcasts," from 1940 to 2000 for northern Wisconsin to examine "rural sprawl" in northern Wisconsin and its relationship to forested areas and public lands. We integrated housing density estimates with the 1992/1993 National Land Cover Dataset to examine the relationship between rural sprawl and land cover, especially forests. Between 1940 and 2000, private land with <2 housing units/km(2) decreased from 47% to 21% of the total landscape. Most importantly, housing growth was concentrated along the boundaries of public lands. In 14 of the 19 counties that we studied, housing growth rates within 1 km of a public land boundary exceeded growth rates in the remainder of the county, and three of the five counties that did not exhibit this pattern, were the ones with the least amount of public land. Future growth can be expected in areas with abundant natural amenities, highlighting the critical need for additional research and effective natural resource management and regional planning to address these challenges.

  3. Evaluating carbon storage, timber harvest, and habitat possibilities for a Western Cascades (USA) forest landscape

    Treesearch

    Jeff Kline; Mark E. Harmon; Thomas A. Spies; Anita T. Morzillo; Robert J. Pabst; Brenda C. McComb; Frank Schnekenburger; Keith A. Olsen; Blair Csuti; Jody C. Vogeler

    2016-01-01

    Forest policymakers and managers have long sought ways to evaluate the capability of forest landscapes to jointly produce timber, habitat, and other ecosystem services in response to forest management. Currently, carbon is of particular interest as policies for increasing carbon storage on federal lands are being proposed. However, a challenge in joint production...

  4. Interim definitions for old growth Douglas-fir and mixed-conifer forests in the Pacific Northwest and California.

    Treesearch

    J.F. Franklin; F. Hall; W. Laudenslayer; C. Maser; J. Nunan; J. Poppino; C.J. Ralph; T. Spies

    1986-01-01

    Interim definitions of old-growth forests are provided to guide efforts in land-management planning until comprehensive definitions based on research that is currently underway can be formulated. The basic criteria for identifying old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and mixed-conifer forests in western Washington and...

  5. EFRs in the Rocky Mountain Research Station: Understanding patterns of forest growth, weather and disturbance [Chapter 2.8

    Treesearch

    G. Sam Foster; Todd Mower; Russell Graham; Theresa B. Jain

    2014-01-01

    How does forest growth integrate weather, insect and disease attach, management actions, and natural disturbance? Which of these has the most impact on forest growth, composition, structure, and change? These questions have animated the activities of scientists of the Rocky Mountain Research Station (RMRS) since its earliest days, and continue to animate our research...

  6. Soil Carbon Storage and Turnover in an Old-Growth Coastal Redwood Forest and Adjacent Prairie

    NASA Astrophysics Data System (ADS)

    McFarlane, K. J.; Torn, M. S.; Mambelli, S.; Dawson, T. E.

    2010-12-01

    Coastal redwood (Sequoia sempervirens) forests store lots of carbon in aboveground tree biomass because redwoods are very long-lived and can grow very large. Redwood is known for its high resistance to decay, a result of high levels of aromatic compounds (tannins) in the tree’s tissues. We tested the hypothesis that because coastal redwoods are highly productive and produce organic matter that is chemically resistant to decay, old-growth redwood forests should store large amounts of stabilized soil carbon. We measured soil C storage to 110 cm depth in an old-growth coastal redwood forest and used physical soil fractionation combined with radiocarbon measurements to determine soil organic matter turnover time. In addition, we measured soil C storage and turnover at an adjacent prairie experiencing the same climate and with soils derived from the same parent material. We found larger soil C stocks to 110 cm at the prairie (350 Mg C ha-1) than the redwood forest (277 Mg C ha-1) even with O-horizons included for the forest. Larger N stocks were also observed at the prairie than the redwood and these differences in stocks were driven by higher C and N concentrations in mineral soils at the prairie. Differences between ecosystems in soil C and N concentrations, C:N ratios, and C and N stocks were observed for the top 50 cm only, suggesting that the influence of the different litter types did not extend to deeper soils. Contrary to what was expected, bulk soil and heavy density-fraction Δ14C values were higher, indicating shorter turnover times, for the redwood forest than the prairie. In summary, we did not observe greater C storage or 14C-based turnover times in old-growth redwood forest compared to adjacent prairie, suggesting chemical recalcitrance of litter inputs does not drive soil C stabilization at these ecosystems.

  7. Increased water deficit decreases Douglas fir growth throughout western US forests

    USGS Publications Warehouse

    Restaino, Christina M; Peterson, David L.; Littell, Jeremy

    2016-01-01

    Changes in tree growth rates can affect tree mortality and forest feedbacks to the global carbon cycle. As air temperature increases, evaporative demand also increases, increasing effective drought in forest ecosystems. Using a spatially comprehensive network of Douglas-fir (Pseudotsuga menziesii) chronologies from 122 locations that experience distinctly different climate in the western United States, we show that increased temperature decreases growth via vapor pressure deficit (VPD) across all latitudes. Under an ensemble of global circulation models, we project an increase in both the mean VPD associated with the lowest growth extremes and the probability of exceeding these VPD values. As temperature continues to increase in future decades, we can expect deficit-related stress to increase and consequently Douglas-fir growth to decrease throughout its US range.

  8. Increased water deficit decreases Douglas fir growth throughout western US forests

    PubMed Central

    Restaino, Christina M.; Peterson, David L.; Littell, Jeremy

    2016-01-01

    Changes in tree growth rates can affect tree mortality and forest feedbacks to the global carbon cycle. As air temperature increases, evaporative demand also increases, increasing effective drought in forest ecosystems. Using a spatially comprehensive network of Douglas fir (Pseudotsuga menziesii) chronologies from 122 locations that represent distinct climate environments in the western United States, we show that increased temperature decreases growth via vapor pressure deficit (VPD) across all latitudes. Using an ensemble of global circulation models, we project an increase in both the mean VPD associated with the lowest growth extremes and the probability of exceeding these VPD values. As temperature continues to increase in future decades, we can expect deficit-related stress to increase and consequently Douglas fir growth to decrease throughout its US range. PMID:27503880

  9. Increased water deficit decreases Douglas fir growth throughout western US forests.

    PubMed

    Restaino, Christina M; Peterson, David L; Littell, Jeremy

    2016-08-23

    Changes in tree growth rates can affect tree mortality and forest feedbacks to the global carbon cycle. As air temperature increases, evaporative demand also increases, increasing effective drought in forest ecosystems. Using a spatially comprehensive network of Douglas fir (Pseudotsuga menziesii) chronologies from 122 locations that represent distinct climate environments in the western United States, we show that increased temperature decreases growth via vapor pressure deficit (VPD) across all latitudes. Using an ensemble of global circulation models, we project an increase in both the mean VPD associated with the lowest growth extremes and the probability of exceeding these VPD values. As temperature continues to increase in future decades, we can expect deficit-related stress to increase and consequently Douglas fir growth to decrease throughout its US range.

  10. Disturbance legacies and climate jointly drive tree growth and mortality in an intensively studied boreal forest.

    PubMed

    Bond-Lamberty, Ben; Rocha, Adrian V; Calvin, Katherine; Holmes, Bruce; Wang, Chuankuan; Goulden, Michael L

    2014-01-01

    Most North American forests are at some stage of post-disturbance regrowth, subject to a changing climate, and exhibit growth and mortality patterns that may not be closely coupled to annual environmental conditions. Distinguishing the possibly interacting effects of these processes is necessary to put short-term studies in a longer term context, and particularly important for the carbon-dense, fire-prone boreal forest. The goals of this study were to combine dendrochronological sampling, inventory records, and machine-learning algorithms to understand how tree growth and death have changed at one highly studied site (Northern Old Black Spruce, NOBS) in the central Canadian boreal forest. Over the 1999-2012 inventory period, mean tree diameter increased even as stand density and basal area declined significantly. Tree mortality averaged 1.4 ± 0.6% yr-(1), with most mortality occurring in medium-sized trees; new recruitment was minimal. There have been at least two, and probably three, significant influxes of new trees since stand initiation, but none in recent decades. A combined tree ring chronology constructed from sampling in 2001, 2004, and 2012 showed several periods of extreme growth depression, with increased mortality lagging depressed growth by ~5 years. Higher minimum and maximum air temperatures exerted a negative influence on tree growth, while precipitation and climate moisture index had a positive effect; both current- and previous-year data exerted significant effects. Models based on these variables explained 23-44% of the ring-width variability. We suggest that past climate extremes led to significant mortality still visible in the current forest structure, with decadal dynamics superimposed on slower patterns of fire and succession. These results have significant implications for our understanding of previous work at NOBS, the carbon sequestration capability of old-growth stands in a disturbance-prone landscape, and the sustainable management of

  11. Predicting impacts of future human population growth and development on occupancy rates of forest-dependent birds

    USGS Publications Warehouse

    Brown, Michelle L.; Donovan, Therese; Schwenk, W. Scott; Theobald, David M.

    2014-01-01

    Forest loss and fragmentation are among the largest threats to forest-dwelling wildlife species today, and projected increases in human population growth are expected to increase these threats in the next century. We combined spatially-explicit growth models with wildlife distribution models to predict the effects of human development on 5 forest-dependent bird species in Vermont, New Hampshire, and Massachusetts, USA. We used single-species occupancy models to derive the probability of occupancy for each species across the study area in the years 2000 and 2050. Over half a million new housing units were predicted to be added to the landscape. The maximum change in housing density was nearly 30 houses per hectare; however, 30% of the towns in the study area were projected to add less than 1 housing unit per hectare. In the face of predicted human growth, the overall occupancy of each species decreased by as much as 38% (ranging from 19% to 38% declines in the worst-case scenario) in the year 2050. These declines were greater outside of protected areas than within protected lands. Ninety-seven percent of towns experienced some decline in species occupancy within their borders, highlighting the value of spatially-explicit models. The mean decrease in occupancy probability within towns ranged from 3% for hairy woodpecker to 8% for ovenbird and hermit thrush. Reductions in occupancy probability occurred on the perimeters of cities and towns where exurban development is predicted to increase in the study area. This spatial approach to wildlife planning provides data to evaluate trade-offs between development scenarios and forest-dependent wildlife species.

  12. Carbon dioxide exchange between an undisturbed old-growth temperate forest and the atmosphere

    Treesearch

    D.Y. Hollinger; F.M. Kelliher; J.N. Byers; J.E. Hunt; T.M. McSeveny; P.L. Weir

    1994-01-01

    We used the eddy-correlation technique to investigate the exchange of C02 between an undisturbed old-growth forest and the atmosphere at a remote Southern Hemisphere site on 15 d between 1989 and 1990. Our goal was to determine how environmental factors regulate ecosystem CO2 exchange, and to test whether present knowledge...

  13. Application of linked regional scale growth, biogeography, and economic models for southeastern United States pine forests

    Treesearch

    Steven G. McNulty; Jennifer A. Moore; Louis Iverson; Anantha Prasad; Robert, et al. Abt

    2000-01-01

    The southern United States produces over 50% of commercial timber harvests in the US and the demand for southern timber are likely to increase in the future. Global change is altering the physical and chemical environmental which will play a major role in determining future forest stand growth, insect and disease outbreaks, regeneration success, and distribution of...

  14. Development of second-growth northern hardwoods on Bartlett Experimental Forest - a 25-year record

    Treesearch

    William B. Leak

    1961-01-01

    Second-growth timber occupies more than one-third of the commercial northern hardwood forest land in New England. The origin of these stands - clearcutting, or land abandonment with or without fire - determined their present characteristics; they are essentially even-aged, with a high proportion of intolerant and intermediate species and many stems of sprout origin (...

  15. Seedling survival and growth of three forest tree species: The role of spatial heterogeneity

    Treesearch

    Brian Beckage; James S. Clark

    2003-01-01

    Spatial heterogeneity in microenvironments may provide unique regeneration niches for trees and may promote forest diversity. We examined how heterogeneity in understory cover, mineral nutrients, and moisture and their interactions with canopy gaps contribute to the coexistence of three common, co-occuring tree species. We measured survival and height growth of 1080...

  16. Decomposition of coarse woody debris originating by clearcutting of an old-growth conifer forest

    Treesearch

    Jack E. Janisch; Mark E. Harmon; Hua Chen; Becky Fasth; Jay Sexton

    2005-01-01

    Decomposition constants (k) for aboveground logs and stumps and subsurface coarse roots originating from harvested old-growth forest (estimated age 400 to 600 y) were assessed by volume-density change methods along a 70-y chronosequence of clearcuts on the Wind River Ranger District, Washington, USA. Principal species sampled were Tsuga heterophylla...

  17. Hydraulic redistribution of soil water in two old-growth coniferous forests: quantifying patterns and controls.

    Treesearch

    J.M. Warren; F.C. Meinzer; J.R. Brooks; J.-C. Domec; R. Coulombe

    2006-01-01

    We incorporated soil/plant biophysical properties into a simple model to predict seasonal trajectories of hydraulic redistribution (HR). We measured soil water content, water potential root conductivity, and climate across multiple years in two old-growth coniferous forests. The HR variability within sites (0 to 0.5 mm/d) was linked to spatial patterns of roots, soil...

  18. Interannual climatic variation mediates elevated CO2 and O3 effects on forest growth

    Treesearch

    Mark E. Kubiske; Vanessa A. Quinn; Warren E. Heilman; Evan P. McDonald; Paula E. Marquardt; Ron M. Teclaw; Alexander L. Friend; David F. Karnosky

    2006-01-01

    We analyzed growth data from model aspen (Populus tremuloides Michx.) forest ecosystems grown in elevated atmospheric carbon dioxide ([CO2]; 518?LL-1) and ozone concentrations ([O3]; 1.5 x background of 30-40 nL L-1 during daylight hours) for 7 years using...

  19. Application of Linked Regional Scale Growth, Biogeography, and Economic Models for Southeastern United States Pine Forests

    Treesearch

    Steven G. McNulty; Jennifer A. Moore; Louis Iverson; Anantha Prasad; Robert Abt; Bryan Smith; Ge Sun; Michael Gavazzi; John Bartlett; Brian Murray; Robert A. Mickler; John D. Aber

    2000-01-01

    The southern United States produces over 50% of commercial timber harvests in the US and the demand for southern timber are likely to increase in the future. Global change is altering the physical and chemical environmental which will play a major role in determining future forest stand growth, insect and disease outbreaks, regeneration success, and distribution of...

  20. Patterns of diametric growth in stem-analyzed laurel trees (Cordia alliodora) in a Panamanian forest

    Treesearch

    Bernard R Parresol; Margaret S. Devall

    2013-01-01

    Based on cross-dated increment cores, yearly diameters of trees were reconstructed for 21 laurels (Cordia alliodora) growing in a natural secondary forest on Gigante Peninsula, Panama. From this sample of dominant-codominant trees, ages were 14–35 years with an average of 25 years. Growth typically slowed at 7 years old, indicating effects of...

  1. Plot intensity and cycle-length effects on growth and removals estimates from forest inventories

    Treesearch

    Paul C. Van Deusen; Francis A. Roesch

    2015-01-01

    Continuous forest inventory planners can allocate the budget to more plots per acre or a shorter remeasurement cycle. A higher plot intensity benefits small area estimation and allows for more precision in current status estimates. Shorter cycles may provide better estimates of growth, removals and mortality. On a fixed budget, the planner can't have both greater...

  2. Ground-based forest harvesting effects on soil physical properties and Douglas-fir growth.

    Treesearch

    Adrian Ares; Thomas A. Terry; Richard E. Miller; Harry W. Anderson; Barry L. Flaming

    2005-01-01

    Soil properties and forest productivity can be affected by heavy equipment used for harvest and site preparation but these impacts vary greatly with site conditions and operational practices. We assessed the effects of ground-based logging on soil physical properties and subsequent Douglas-fir [Pseudotsuga menziesii (Mirb) Franco] growth on a highly...

  3. Establishment, survival, and growth of selected browse species in a ponderosa pine forest

    USGS Publications Warehouse

    Dietz, D.R.; Uresk, D.W.; Messner, H.E.; McEwen, L.C.

    1980-01-01

    Information is presented on establishment, survival, and growth of seven selected browse species in a ponderosa pine forest over a 10-year period. Methods of establishment included hand seeding and planting bare-root and containerized stock. Success of different methods differed with shrub species.

  4. Ground-flora communities of headwater riparian areas in an old-growth central hardwood forest

    Treesearch

    P. Charles Goebel; David M. Hix; Clayton E. Dygert; Kathryn L. Holmes

    2003-01-01

    The composition and structure of ground-flora vegetation was examined across headwater riparian areas of Johnson Woods, an old-growth forest located in northcentral Ohio. While the distribution patterns of these species groups is variable, classification and gradient analyses indicate that ground-flora vegetation is related strongly to landform and distance from the...

  5. Coarse Woody Debris Ecology in a Second-Growth Sequoia sempervirens Forest Stream

    Treesearch

    Matthew D. O' Connor; Robert R. Ziemer

    1989-01-01

    Coarse woody debris (CWD) contributes to high quality habitat for anadromous fish. CWD volume, species, and input mechanisms was inventoried in North Fork Caspar Creek to assess rates of accumulation and dominant sources of CWD in a 100-year-old second-growth redwood (Sequoia sempervirens) forest. CWD accumulation in the active stream channel and in...

  6. Do remnant old-growth trees accelerate rates of succession in mature Douglas-fir forests?

    Treesearch

    William S. Keeton; Jerry F. Franklin

    2005-01-01

    Biological legacies left by natural disturbances provide ecological functions throughout forest stand development, but their influences on processes of ecological succession are not completely understood. We investigated the successional role of one type of biological legacy: remnant old-growth trees persisting in mature Pseudotsuga menziesii (...

  7. Generalization of Faustmann's Formula for Stochastic Forest Growth and Prices with Markov Decision Process Models

    Treesearch

    Joseph Buongiorno

    2001-01-01

    Faustmann's formula gives the land value, or the forest value of land with trees, under deterministic assumptions regarding future stand growth and prices, over an infinite horizon. Markov decision process (MDP) models generalize Faustmann's approach by recognizing that future stand states and prices are known only as probabilistic distributions. The...

  8. Composition and structure of an old-growth floodplain forest of the lower Kaskaskia River

    Treesearch

    John B. Taft

    2003-01-01

    Compositional and structural properties of canopy, shrub/sapling, and ground-cover strata were measured within an old-growth floodplain forest bordering the lower Kaskaskia River in southwestern Illinois. Basal area for trees was estimated at 31.8 m²/ha, tree density was 398 trees/ha with 27 species recorded in the canopy stratum. The dominant tree species...

  9. Notes on Some Old-Growth Forests in Ohio, Indiana, and Illinois

    Treesearch

    John T. Auten

    1941-01-01

    The disturbing increase in acreage of abandoned land in the Central States has heightened interest in the region's few remnants of old-growth hardwood forest. Studies are being made to determine what kinds of trees originally grew on different kinds of soil, what was the original character of the soil, how many trees grew on an acre, and how large the trees were...

  10. Population growth and the decline of natural Southern yellow pine forests

    Treesearch

    David B. South; Edward R. Buckner

    2004-01-01

    Population growth has created social and economic pressures that affect the sustainability of naturally regenerated southern yellow pine forests. Major causes of this decline include (1) a shift in public attitudes regarding woods burning (from one favoring it to one that favors fire suppression) and (2) an increase in land values (especially near urban centers). The...

  11. Climate indices strongly influence old-growth forest carbon exchange

    Treesearch

    Sonia Wharton; Matthias Falk

    2016-01-01

    We present a decade and a half (1998–2013) of carbon dioxide fluxes from an old-growth stand in the American Pacific Northwest to identify ecosystem-level responses to Pacific teleconnection patterns, including the El Niño/Southern Oscillation (ENSO). This study provides the longest, continuous record of old-growth eddy flux data to date from one of the longest running...

  12. The Dynamic of Annual Carbon Allocation to Wood in European Forests Is Consistent with a Combined Source-Sink Limitation of Growth: Implications on Growth Simulations in a Terrestrial Biosphere Model

    NASA Astrophysics Data System (ADS)

    Guillemot, J.; Martin-StPaul, N. K.; Dufrêne, E.; François, C.; Soudani, K.; Ourcival, J. M.; Leadley, P.; Delpierre, N.

    2014-12-01

    The extent to which forest growth is limited by carbon (C) supply (source control) or by cambial activity (sink control) will strongly determines the responses of trees to global changes. However, the physiological processes responsible for the limitation of forest growth are still under debate. The aim of this study was i) to evaluate the key drivers of the annual carbon allocation to wood along large soil and climate regional gradients in four tree species representative of the main European forest biomes (Fagus sylvatica, Quercus petraea, Quercus ilex and Picea abies) ii) to implement the identified key drivers in a new C allocation scheme within the CASTANEA terrestrial biosphere model (TBM). Combining field measurements and process-based simulations at 49 sites (931 site-years), our analyses revealed that the inter-site variability in C allocation to wood was predominantly driven by an age-related decline. The direct control of temperature or water stress on sink activity (i.e. independently from their effects on C supply) exerted a strong influence on the annual woody growth in all the species considered, including deciduous temperate species. The lagged effect of the past environment conditions was a significant driver of the annual C allocation to wood. Carbon supply appeared to strongly limit growth only in deciduous temperate species. Our study supports the premise that European forest growth is under a complex panel of source- and sink- limitations, contradicting the simple source control implemented in most TBMs. The implementation of these combined forest growth limitations in the CASTANEA model significantly improved its performance when evaluated against independent stand growth data at the regional scale (mainland France, >103 plots). We finally discuss how the sink imitation affects the CASTANEA simulated projections of forest productivity along the 21th century, especially with respect to the expected fertilizing effect of increasing atmospheric

  13. Influence of light conditions on the allometry and growth of the understory palm Geonoma undata subsp. edulis (Arecaceae) of neotropical cloud forests.

    PubMed

    Sylvester, Olivia; Avalos, Gerardo

    2013-12-01

    Knowledge on the growth responses of understory palms to changing light conditions within neotropical cloud forests is limited. The low light regime of these environments, in addition to persistent cloudiness, low ambient temperatures, and slow nutrient cycles, imposes significant constraints on biomass accumulation. Here, we evaluate how changes in the understory light conditions influenced the allometry and growth of G. undata subsp. edulis in two cloud forests in Costa Rica. We examined the structural relationships between stem diameter, stem height, and crown area in reproductive and nonreproductive individuals. We related the variation in stem growth and crown area with allometry, leaf production and longevity, and light conditions that we measured using hemispherical photographs over 1 year. The allometric and growth pattern of G. undata subsp. edulis was characterized by its investment in crown area, which was strongly and positively related to increments in palm height and reproduction. Growth, measured as the increase in crown area and stem height, was not explained by the variation in the light regime spanning 1 year. However, reproductive individuals were generally taller, more slender, and had larger leaf areas than nonreproductive individuals. Our results demonstrated that stem growth responses were mostly controlled by initial crown size rather than by temporal differences in the understory light regimes of cloud forests. These results suggest that cloud forest understory palms have a limited capacity to respond to light changes and rely mostly on an opportunistic strategy for biomass accumulation and reproduction.

  14. Forests on the edge: evaluating contributions of and threats to America's private forest lands

    Treesearch

    Susan M. Stein; Mark Hatfield; Ronald E. McRoberts; Dacia M. Meneguzzo; Mike Dechter; < i> et al< /i>

    2007-01-01

    The Forests on the Edge project, sponsored by the U.S. Department of Agriculture Forest Service, uses geographic information systems to construct and analyze maps depicting ecological, social, and economic contributions of America's private forest lands and threats to those contributions. Watersheds across the conterminous United States are ranked relative to the...

  15. Discrimination between acute and chronic decline of Central European forests using map algebra of the growth condition and forest biomass fuzzy sets: A case study.

    PubMed

    Samec, Pavel; Caha, Jan; Zapletal, Miloš; Tuček, Pavel; Cudlín, Pavel; Kučera, Miloš

    2017-12-01

    Forest decline is either caused by damage or else by vulnerability due to unfavourable growth conditions or due to unnatural silvicultural systems. Here, we assess forest decline in the Czech Republic (Central Europe) using fuzzy functions, fuzzy sets and fuzzy rating of ecosystem properties over a 1×1km grid. The model was divided into fuzzy functions of the abiotic predictors of growth conditions (Fpred including temperature, precipitation, acid deposition, soil data and relative site insolation) and forest biomass receptors (Frec including remote sensing data, density and volume of aboveground biomass, and surface humus chemical data). Fuzzy functions were designed at the limits of unfavourable, undetermined or favourable effects on the forest ecosystem health status. Fuzzy sets were distinguished through similarity in a particular membership of the properties at the limits of the forest status margins. Fuzzy rating was obtained from the least difference of Fpred-Frec. Unfavourable Fpred within unfavourable Frec indicated chronic damage, favourable Fpred within unfavourable Frec indicated acute damage, and unfavourable Fpred within favourable Frec indicated vulnerability. The model in the 1×1km grid was validated through spatial intersection with a point field of uniform forest stands. Favourable status was characterised by soil base saturation (BS)>50%, BCC/Al>1, Corg>1%, MgO>6g/kg, and nitrogen deposition<1200mol(H(+))/ha·year. Vulnerable forests had BShumus 46-60%, BCC/Al 9-20 and NDVI≈0.42. Chronic forest damage occurs in areas with low temperatures, high nitrogen deposition, and low soil BS and Corg levels. In the Czech Republic, 10% of forests were considered non-damaged and 77% vulnerable, with damage considered acute in 7% of forests and chronic in 5%. The fuzzy model used suggests that improvement in forest health will depend on decreasing environmental load and restoration concordance between growth conditions and tree species composition

  16. Long-term growth decline in Toona ciliata in a moist tropical forest in Bangladesh: Impact of global warming

    NASA Astrophysics Data System (ADS)

    Rahman, Mizanur; Islam, Rofiqul; Islam, Mahmuda

    2017-04-01

    Tropical forests are carbon rich ecosystems and small changes in tropical forest tree growth substantially influence the global carbon cycle. Forest monitoring studies report inconsistent growth changes in tropical forest trees over the past decades. Most of the studies highlighted changes in the forest level carbon gain, neglecting the species-specific growth changes which ultimately determine community-level responses. Tree-ring analysis can provide historical data on species-specific tree growth with annual resolution. Such studies are inadequate in Bangladesh, which is one of the most climate sensitive regions in the tropics. In this study, we investigated long-term growth rates of Toona ciliata in a moist tropical forest of Bangladesh by using tree-ring analysis. We sampled 50 trees of varying size, obtained increment cores from these trees and measured tree-ring width. Analyses of growth patterns revealed size-dependent growth increments. After correcting for the effect of tree size on tree growth (ontogenetic changes) by two different methods we found declining growth rates in T. ciliata from 1960 to 2013. Standardized ring-width index (RWI) was strongly negatively correlated with annual mean and maximum temperatures suggesting that rising temperature might cause the observed growth decline in T. ciliata. Assuming that global temperatures will rise at the current rate, the observed growth decline is assumed to continue. The analysis of stable carbon and oxygen isotopes may reveal more insight on the physiological response of this species to future climatic changes.

  17. Long-term forest resilience to climate change indicated by mortality, regeneration, and growth in semiarid southern Siberia.

    PubMed

    Xu, Chongyang; Liu, Hongyan; Anenkhonov, Oleg A; Korolyuk, Andrey Yu; Sandanov, Denis V; Balsanova, Larisa D; Naidanov, Bulat B; Wu, Xiuchen

    2017-06-01

    Several studies have documented that regional climate warming and the resulting increase in drought stress have triggered increased tree mortality in semiarid forests with unavoidable impacts on regional and global carbon sequestration. Although climate warming is projected to continue into the future, studies examining long-term resilience of semiarid forests against climate change are limited. In this study, long-term forest resilience was defined as the capacity of forest recruitment to compensate for losses from mortality. We observed an obvious change in long-term forest resilience along a local aridity gradient by reconstructing tree growth trend and disturbance history and investigating postdisturbance regeneration in semiarid forests in southern Siberia. In our study, with increased severity of local aridity, forests became vulnerable to drought stress, and regeneration first accelerated and then ceased. Radial growth of trees during 1900-2012 was also relatively stable on the moderately arid site. Furthermore, we found that smaller forest patches always have relatively weaker resilience under the same climatic conditions. Our results imply a relatively higher resilience in arid timberline forest patches than in continuous forests; however, further climate warming and increased drought could possibly cause the disappearance of small forest patches around the arid tree line. This study sheds light on climate change adaptation and provides insight into managing vulnerable semiarid forests. © 2016 John Wiley & Sons Ltd.

  18. A Hierarchical Analysis of Tree Growth and Environmental Drivers Across Eastern US Temperate Forests

    NASA Astrophysics Data System (ADS)

    Mantooth, J.; Dietze, M.

    2014-12-01

    Improving predictions of how forests in the eastern United States will respond to future global change requires a better understanding of the drivers of variability in tree growth rates. Current inventory data lack the temporal resolution to characterize interannual variability, while existing growth records lack the extent required to assess spatial scales of variability. Therefore, we established a network of forest inventory plots across ten sites across the eastern US, and measured growth in adult trees using increment cores. Sites were chosen to maximize climate space explored, while within sites, plots were spread across primary environmental gradients to explore landscape-level variability in growth. Using the annual growth record available from tree cores, we explored the responses of trees to multiple environmental covariates over multiple spatial and temporal scales. We hypothesized that within and across sites growth rates vary among species, and that intraspecific growth rates increase with temperature along a species' range. We also hypothesized that trees show synchrony in growth responses to landscape-scale climatic changes. Initial analyses of growth increments indicate that across sites, trees with intermediate shade tolerance, e.g. Red Oak (Quercus rubra), tend to have the highest growth rates. At the site level, there is evidence for synchrony in response to large-scale climatic events (e.g. prolonged drought and above average temperatures). However, growth responses to climate at the landscape scale have yet to be detected. Our current analysis utilizes hierarchical Bayesian state-space modeling to focus on growth responses of adult trees to environmental covariates at multiple spatial and temporal scales. This predictive model of tree growth currently incorporates observed effects at the individual, plot, site, and landscape scale. Current analysis using this model shows a potential slowing of growth in the past decade for two sites in the

  19. Fix success and accuracy of GPS radio collars in old-growth temperate coniferous forests

    USGS Publications Warehouse

    Sager-Fradkin, Kimberly A.; Jenkins, Kurt J.; Hoffman, Robert L.; Happe, P.; Beecham, J.; Wright, R.G.

    2007-01-01

    Global Positioning System (GPS) telemetry is used extensively to study animal distribution and resource selection patterns but is susceptible to biases resulting from data omission and spatial inaccuracies. These data errors may cause misinterpretation of wildlife habitat selection or spatial use patterns. We used both stationary test collars and collared free-ranging American black bears (Ursus americanus) to quantify systemic data loss and location error of GPS telemetry in mountainous, old-growth temperate forests of Olympic National Park, Washington, USA. We developed predictive models of environmental factors that influence the probability of obtaining GPS locations and evaluated the ability of weighting factors derived from these models to mitigate data omission biases from collared bears. We also examined the effects of microhabitat on collar fix success rate and examined collar accuracy as related to elevation changes between successive fixes. The probability of collars successfully obtaining location fixes was positively associated with elevation and unobstructed satellite view and was negatively affected by the interaction of overstory canopy and satellite view. Test collars were 33% more successful at acquiring fixes than those on bears. Fix success rates of collared bears varied seasonally and diurnally. Application of weighting factors to individual collared bear fixes recouped only 6% of lost data and failed to reduce seasonal or diurnal variation in fix success, suggesting that variables not included in our model contributed to data loss. Test collars placed to mimic bear bedding sites received 16% fewer fixes than randomly placed collars, indicating that microhabitat selection may contribute to data loss for wildlife equipped with GPS collars. Horizontal collar errors of >800 m occurred when elevation changes between successive fixes were >400 m. We conclude that significant limitations remain in accounting for data loss and error inherent in using

  20. Sapling biomass allocation and growth in the understory of a deciduous hardwood forest.

    PubMed

    Delucia, E; Sipe, T; Herrick, J; Maherali, H

    1998-07-01

    Above- and belowground tissues of co-occurring saplings (0.1-1 m height) of Acer saccharum Marsh. (very shade tolerant), Acer rubrum L. (shade tolerant), Fraxinus americana L. (intermediate shade tolerant), and Prunus serotina Ehrh. (shade intolerant) were harvested from a forest understory to test the hypothesis that the pattern of biomass allocation varied predictably with shade-tolerance rank. The placement and length of branches along the main axis were consistent with the formation of a monolayer of foliage for the tolerant and intermediate species. Other morphological characteristics did not vary predictably with shade-tolerance rank. The maintenance of high specific leaf area (SLA; leaf area/leaf mass) and leaf area ratio (LAR; leaf area/sapling mass) is considered important for growth under extreme shade, yet these traits were not clearly related to the shade-tolerance rank of these species. Fraxinus americana, an intermediate species, had the highest LAR and growth rate in the understory, and with the exception of P. serotina, the very shade-tolerant A. saccharum had the lowest LAR. Prunus serotina maintained a large starch-rich tap root and shoot dieback was common, yielding the largest root/shoot ratio for these species. The observed allocation patterns were not similar to the long-standing expectation for the phenotypic response of juvenile trees to shade, but were consistent with three hypothetical "growth strategies" in the understory: (1) the low SLA and LAR of A. saccharum may provide a measure of defense against herbivores and pathogens and thus promote persistence in the understory, (2) the high SLA for F. americana and high LAR for F. americana and A. rubrum may enable these species to achieve high growth rates in shade, and (3) the large carbohydrate stores of P. serotina may poise this species for opportunistic growth following disturbance. The relative importance of resistance to herbivores and pathogens vs. the maintenance of high growth

  1. Abundance and Size Distribution of Cavity Trees in Second-Growth and Old-Growth Central Hardwood Forests

    Treesearch

    Zhaofei Fan; Stephen R. Shifley; Martin A. Spetich; Frank R. Thompson III; David R. Larsen

    2005-01-01

    In central hardwood forests, mean cavity-tree abundance increases with increasing standsize class (seedling/sapling, pole, sawtimber, old-growth). However, within a size class, the number of cavity trees is highly variable among 0.1-ha inventory plots. Plots in young stands are most likely to have no cavity trees, but some plots may have more than 50 cavity trees/ha....

  2. Abundance and size distribution of cavity trees in second-growth and old-growth central hardwood forests

    Treesearch

    Zhaofei Fan; Stephen R. Shifley; Martin A. Spetich; Frank R. Thompson; David R. Larsen

    2005-01-01

    In central hardwood forests, mean cavity-tree abundance increases with increasing standsize class (seedling/sapling, pole, sawtimber, old-growth). However, within a size class, the number of cavity trees is highly variable among 0.1-ha inventory plots. Plots in young stands are most likely to have no cavity trees, but some plots may have more than 50 cavity trees/ha....

  3. Forty-two years of change in an old-growth and second-growth beech-maple forest of north central Ohio

    Treesearch

    Natalie R. Pinheiro; P. Charles Goebel; David M. Hix

    2008-01-01

    Using data collected in 1964 and 2006, we examined changes in the composition and structure of a second-growth and old-growth beech-maple forest of Crall Woods, located in Ashland County of north central Ohio. Over the 42 years, the old-growth forest (estimated to be at least 250 years old) experienced a significant shift in species composition as American beech,...

  4. Windthrow and salvage logging in an old-growth hemlock-northern hardwoods forest

    USGS Publications Warehouse

    Lang, K.D.; Schulte, L.A.; Guntenspergen, G.R.

    2009-01-01

    Although the initial response to salvage (also known as, post-disturbance or sanitary) logging is known to vary among system components, little is known about longer term forest recovery. We examine forest overstory, understory, soil, and microtopographic response 25 years after a 1977 severe wind disturbance on the Flambeau River State Forest in Wisconsin, USA, a portion of which was salvage logged. Within this former old-growth hemlock-northern hardwoods forest, tree dominance has shifted from Eastern hemlock (Tsuga canadensis) to broad-leaf deciduous species (Ulmus americana, Acer saccharum, Tilia americana, Populus tremuloides, and Betula alleghaniensis) in both the salvaged and unsalvaged areas. While the biological legacies of pre-disturbance seedlings, saplings, and mature trees were initially more abundant in the unsalvaged area, regeneration through root suckers and stump sprouts was common in both areas. After 25 years, tree basal area, sapling density, shrub layer density, and seedling cover had converged between unsalvaged and salvaged areas. In contrast, understory herb communities differed between salvaged and unsalvaged forest, with salvaged forest containing significantly higher understory herb richness and cover, and greater dominance of species benefiting from disturbance, especially Solidago species. Soil bulk density, pH, organic carbon content, and organic nitrogen content were also significantly higher in the salvaged area. The structural legacy of tip-up microtopography remains more pronounced in the unsalvaged area, with significantly taller tip-up mounds and deeper pits. Mosses and some forest herbs, including Athyrium filix-femina and Hydrophyllum virginianum, showed strong positive responses to this tip-up microrelief, highlighting the importance of these structural legacies for understory biodiversity. In sum, although the pathways of recovery differed, this forest appeared to be as resilient to the compound disturbances of windthrow

  5. Modeling transcriptional networks regulating secondary growth and wood formation in forest trees.

    PubMed

    Liu, Lijun; Filkov, Vladimir; Groover, Andrew

    2014-06-01

    The complex interactions among the genes that underlie a biological process can be modeled and presented as a transcriptional network, in which genes (nodes) and their interactions (edges) are shown in a graphical form similar to a wiring diagram. A large number of genes have been identified that are expressed during the radial woody growth of tree stems (secondary growth), but a comprehensive understanding of how these genes interact to influence woody growth is currently lacking. Modeling transcriptional networks has recently been made tractable by next-generation sequencing-based technologies that can comprehensively catalog gene expression and transcription factor-binding genome-wide, but has not yet been extensively applied to undomesticated tree species or woody growth. Here we discuss basic features of transcriptional networks, approaches for modeling biological networks, and examples of biological network models developed for forest trees to date. We discuss how transcriptional network research is being developed in the model forest tree genus, Populus, and how this research area can be further developed and applied. Transcriptional network models for forest tree secondary growth and wood formation could ultimately provide new predictive models to accelerate hypothesis-driven research and develop new breeding applications. © 2013 Scandinavian Plant Physiology Society.

  6. A high-resolution monitoring network investigating stem growth of tropical forest trees

    NASA Astrophysics Data System (ADS)

    Hofhansl, F.; De Araujo, A. C.; DeLucia, E. H.

    2015-12-01

    The proportion of carbon (C) allocated to tree stems is an important determinant of the C sink-strength of global forest ecosystems. Understanding the mechanisms controlling stem growth is essential for parameterization of global vegetation models and to accurately predict C sequestration of forest ecosystems. However, we still lack a thorough understanding of intra-annual variations in stem growth of tropical forest ecosystems, which could be especially prone to projected climatic changes. We here present high-resolution data (≤ 6 µm; ≥ 1 min) from a novel monitoring network of wireless devices for automated measurement of expansion and contraction in tree diameter using a membrane potentiometer, as well as point dendrometers on phloem and xylem to analyze diurnal changes in stem growth. Our results indicate that diurnal changes in stem diameter were associated with sap flow and related to seasonal variations in daytime temperature and water availability, such that daily maximum stem growth was positively related to temperature during the wet season but showed the opposite trend during the onset of the dry season. We show that high-resolution monitoring of stem growth of tropical trees is crucial to determine the response to intra-annual climate variation and therefore will be key to accurately predict future responses of tropical aboveground C storage, and should be of special interest for tropical ecosystem research and earth system science.

  7. Integrating carbon nanotube forests into polysilicon MEMS: Growth kinetics, mechanisms, and adhesion

    SciTech Connect

    Ubnoske, Stephen M.; Radauscher, Erich J.; Meshot, Eric R.; Stoner, Brian R.; Parker, Charles B.; Glass, Jeffrey T.

    2016-11-19

    The growth of carbon nanotubes (CNTs) on polycrystalline silicon substrates was studied to improve the design of CNT field emission sources for microelectromechanical systems (MEMS) applications and vacuum microelectronic devices (VMDs). Microwave plasma-enhanced chemical vapor deposition (PECVD) was used for CNT growth, resulting in CNTs that incorporate the catalyst particle at their base. The kinetics of CNT growth on polysilicon were compared to growth on Si (100) using the model of Deal and Grove, finding activation energies of 1.61 and 1.54 eV for the nucleation phase of growth and 1.90 and 3.69 eV for the diffusion-limited phase on Si (100) and polysilicon, respectively. Diffusivity values for growth on polysilicon were notably lower than the corresponding values on Si (100) and the growth process became diffusion-limited earlier. Evidence favors a surface diffusion growth mechanism involving diffusion of carbon precursor species along the length of the CNT forest to the catalyst at the base. Explanations for the differences in activation energies and diffusivities were elucidated by SEM analysis of the catalyst nanoparticle arrays and through wide-angle X-ray scattering (WAXS) of CNT forests. As a result, methods are presented to improve adhesion of CNT films during operation as field emitters, resulting in a 2.5× improvement.

  8. Integrating carbon nanotube forests into polysilicon MEMS: Growth kinetics, mechanisms, and adhesion

    DOE PAGES

    Ubnoske, Stephen M.; Radauscher, Erich J.; Meshot, Eric R.; ...

    2016-11-19

    The growth of carbon nanotubes (CNTs) on polycrystalline silicon substrates was studied to improve the design of CNT field emission sources for microelectromechanical systems (MEMS) applications and vacuum microelectronic devices (VMDs). Microwave plasma-enhanced chemical vapor deposition (PECVD) was used for CNT growth, resulting in CNTs that incorporate the catalyst particle at their base. The kinetics of CNT growth on polysilicon were compared to growth on Si (100) using the model of Deal and Grove, finding activation energies of 1.61 and 1.54 eV for the nucleation phase of growth and 1.90 and 3.69 eV for the diffusion-limited phase on Si (100)more » and polysilicon, respectively. Diffusivity values for growth on polysilicon were notably lower than the corresponding values on Si (100) and the growth process became diffusion-limited earlier. Evidence favors a surface diffusion growth mechanism involving diffusion of carbon precursor species along the length of the CNT forest to the catalyst at the base. Explanations for the differences in activation energies and diffusivities were elucidated by SEM analysis of the catalyst nanoparticle arrays and through wide-angle X-ray scattering (WAXS) of CNT forests. As a result, methods are presented to improve adhesion of CNT films during operation as field emitters, resulting in a 2.5× improvement.« less

  9. Habitat management for red tree voles in douglas-fir forests. Biology and management of old-growth forests. Forest Service general technical report

    SciTech Connect

    Huff, M.H.; Holthausen, R.S.; Aubry, K.B.

    1992-09-01

    The relations between arboreal rodents and trees causes the animals to be particularly sensitive to the effects of timber harvesting. Among arboreal rodents, the authors consider the red tree vole to be the most vulnerable to local extinctions resulting from the loss or fragmentation of old-growth Douglas-fir forests. Red tree voles are nocturnal, canopy dwelling, and difficult to study. The following habitat characteristics are potentially important for the species: tree species, stand development, tree size, moisture conditions, topographic positions, elevation, and stand size. Based on these characteristics, the authors developed interim management strategies to help sustain or expand existing populations of red tree voles.

  10. Evaluating compact SAR polarimetry for tropical forest monitoring

    NASA Astrophysics Data System (ADS)

    Trisasongko, Bambang H.

    2015-01-01

    Fully polarimetric Synthetic Aperture Radar (SAR) or PolSAR has been proven useful for diverse applications related to environment. Nevertheless, problems are arising since satellite-borne PolSAR requires special arrangements on data acquisition and consumes higher energy for signal transmission. Complexity of data acquisition and analysis can be reduced using compact polarimetry. The technique has been demonstrated to some extent; however, tests on various environments are still required. This paper assesses compact polarimetry on a tropical forest fringe, especially to monitor expanding oil palm estate and forest disturbance, in comparison to fully polarimetric mode. PALSAR data of Manokwari, Indonesia, were collected from JAXA through RA4.1029 project. In this paper, linear 45 degrees transmission is evaluated to detect various land cover classes using Wishart supervised classifier. Tonal discrepancies between both polarimetric modes are evident, suggesting compact polarimetry has limitation to recover information contained in fully polarimetric mode. However, Wishart classification procedure indicates that compact polarimetry is still useful for mapping.

  11. Fuel Treatment Effects on Water Use Efficiency in Western Pine Forests Under Fire Suppression Evaluated Using Tree Ring Carbon Isotopes

    NASA Astrophysics Data System (ADS)

    Taylor, A. H.; Belmecheri, S.; Harris, L. B.

    2016-12-01

    We identified variation on water use efficiency interpreted from carbon 13 in tree ring cellulose in dense ponderosa pines forests in Washington and Arizona. Historically, these forests burned every decade until fires were suppressed beginning in the early twentieth century. The reduction in fire caused large increases in forest density and forest biomass and potential for intense fire. Forests with hazardous fuels are common in the western United States and these types of forests are treated with mechanical thinning and mechanical thinning and burning to reduce hazardous fuels and fire intensity. At each site we extracted tree ring samples from five trees in each treatment type and a control to identify the effects of fuel treatment of concentration of carbon 13 in tree ring cellulose. Water use efficiency as measured by carbon 13 increased after fuel treatments. Treatment effects were larger for the mechanical plus burn treatment than for the mechanical treatment in each study area compared to the control stands Our results suggest that fuel treatments reduce sensitivity of tree growth to climate and increase water use efficiency. Since tree ring carbon 13 is related to plant productivity, carbon 13 in tree rings can be used as a metric of change in ecosystem function for evaluating fuel treatments.

  12. Huckleberry abundance, stand conditions, and use in western Oregon: evaluating the role of forest management.

    Treesearch

    Becky K Kerns; Susan J. Alexander; John D. Bailey

    2004-01-01

    Huckleberries are major components of the understory vegetation in coniferous Pacific Northwest forests of the United States. Vaccinium species also have a long history of human use. However, little research has been done to ascertain how they respond to common forest management practices. We used data obtained from old-growth, young thinned, and...

  13. The growth-defense trade-off and habitat specialization by plants in Amazonian forests.

    PubMed

    Fine, Paul V A; Miller, Zachariah J; Mesones, Italo; Irazuzta, Sebastian; Appel, Heidi M; Stevens, M Henry H; Sääksjärvi, Ilari; Schultz, Jack C; Coley, Phyllis D

    2006-07-01

    Tropical forests include a diversity of habitats, which has led to specialization in plants. Near Iquitos, in the Peruvian Amazon, nutrient-rich clay forests surround nutrient-poor white-sand forests, each harboring a unique composition of habitat specialist trees. We tested the hypothesis that the combination of impoverished soils and herbivory creates strong natural selection for plant defenses in white-sand forest, while rapid growth is favored in clay forests. Recently, we reported evidence from a reciprocal-transplant experiment that manipulated the presence of herbivores and involved 20 species from six genera, including phylogenetically independent pairs of closely related white-sand and clay specialists. When protected from herbivores, clay specialists exhibited faster growth rates than white-sand specialists in both habitats. But, when unprotected, white-sand specialists outperformed clay specialists in white-sand habitat, and clay specialists outperformed white-sand specialists in clay habitat. Here we test further the hypothesis that the growth defense trade-off contributes to habitat specialization by comparing patterns of growth, herbivory, and defensive traits in these same six genera of white-sand and clay specialists. While the probability of herbivore attack did not differ between the two habitats, an artificial defoliation experiment showed that the impact of herbivory on plant mortality was significantly greater in white-sand forests. We quantified the amount of terpenes, phenolics, leaf toughness, and available foliar protein for the plants in the experiment. Different genera invested in different defensive strategies, and we found strong evidence for phylogenetic constraint in defense type. Overall, however, we found significantly higher total defense investment for white-sand specialists, relative to their clay specialist congeners. Furthermore, herbivore resistance consistently exhibited a significant trade-off against growth rate in each of

  14. Thirty-two years of change in an old-growth Ohio beech-maple forest.

    PubMed

    Runkle, James R

    2013-05-01

    Old-growth forests dominated by understory-tolerant tree species are among forest types most likely to be in equilibrium. However, documentation of the degree to which they are in equilibrium over decades-long time periods is lacking. Changes in climate, pathogens, and land use all are likely to impact stand characteristics and species composition, even in these forests. Here, 32 years of vegetation changes in an old-growth beech (Fagus grandifolia)-sugar maple (Acer saccharum) forest in Hueston Woods, southwest Ohio, USA, are summarized. These changes involve canopy composition and structure, turnover in snags, and development of vegetation in treefall gaps. Stand basal area and canopy density have changed little in 32 years. However, beech has decreased in canopy importance (49% to 32%) while sugar maple has increased (32% to 47%). Annual mortality was about 1.3% throughout the study period. Mortality rates increased with stem size, but the fraction of larger stems increased due to ingrowth from smaller size classes. Beech was represented by more very large stems than small canopy stems: over time, death of those larger stems with inadequate replacement has caused the decrease in beech importance. Sugar maple was represented by more small canopy stems whose growth has increased its importance. The changes in beech and sugar maple relative importance are hypothesized to be due to forest fragmentation mostly from the early 1800s with some possible additional effects associated with the formation of the state park. Snag densities (12-16 snags/ha) and formation rates (1-3 snags.ha(-1).yr(-1)) remained consistent. The treefall gaps previously studied are closing, with a few, large stems remaining. Death of gap border trees occurs consistently enough to favor species able to combine growth in gaps and survival in the understory.

  15. Optimal regeneration planning for old-growth forest: addressing scientific uncertainty in endangered species recovery through adaptive management

    USGS Publications Warehouse

    Moore, C.T.; Conroy, M.J.

    2006-01-01

    Stochastic and structural uncertainties about forest dynamics present challenges in the management of ephemeral habitat conditions for endangered forest species. Maintaining critical foraging and breeding habitat for the endangered red-cockaded woodpecker (Picoides borealis) requires an uninterrupted supply of old-growth forest. We constructed and optimized a dynamic forest growth model for the Piedmont National Wildlife Refuge (Georgia, USA) with the objective of perpetuating a maximum stream of old-growth forest habitat. Our model accommodates stochastic disturbances and hardwood succession rates, and uncertainty about model structure. We produced a regeneration policy that was indexed by current forest state and by current weight of evidence among alternative model forms. We used adaptive stochastic dynamic programming, which anticipates that model probabilities, as well as forest states, may change through time, with consequent evolution of the optimal decision for any given forest state. In light of considerable uncertainty about forest dynamics, we analyzed a set of competing models incorporating extreme, but plausible, parameter values. Under any of these models, forest silviculture practices currently recommended for the creation of woodpecker habitat are suboptimal. We endorse fully adaptive approaches to the management of endangered species habitats in which predictive modeling, monitoring, and assessment are tightly linked.

  16. Evaluating observational methods to quantify snow duration under diverse forest canopies

    NASA Astrophysics Data System (ADS)

    Dickerson-Lange, Susan E.; Lutz, James A.; Martin, Kael A.; Raleigh, Mark S.; Gersonde, Rolf; Lundquist, Jessica D.

    2015-02-01

    Forests cover almost 40% of the seasonally snow-covered regions in North America. However, operational snow networks are located primarily in forest clearings, and optical remote sensing cannot see through tree canopies to detect forest snowpack. Due to the complex influence of the forest on snowpack duration, ground observations in forests are essential. We therefore consider the effectiveness of different strategies to observe snow-covered area under forests. At our study location in the Pacific Northwest, we simultaneously deployed fiber-optic cable, stand-alone ground temperature sensors, and time-lapse digital cameras in three diverse forest treatments: control second-growth forest, thinned forest, and forest gaps (one tree height in diameter). We derived fractional snow-covered area and snow duration metrics from the colocated instruments to assess optimal spatial resolution and sampling configuration, and snow duration differences between forest treatments. The fiber-optic cable and the cameras indicated that mean snow duration was 8 days longer in the gap plots than in the control plots (p < 0.001). We conducted Monte Carlo experiments for observing mean snow duration in a 40 m forest plot, and found the 95% confidence interval was ±5 days for 10 m spacing between instruments and ±3 days for 6 m spacing. We further tested the representativeness of sampling one plot per treatment group by observing snow duration across replicated forest plots at the same elevation, and at a set of forest plots 250 m higher. Relative relationships between snow duration in the forest treatments are consistent between replicated plots, elevation, and two winters of data.

  17. Application of Forest Inventory and Analysis (FIA) data to estimate the amount of old growth forest and snag density in the Northern Region of the National Forest System

    Treesearch

    Raymond L. Czaplewski

    2004-01-01

    This report discusses valid use of data produced by the Forest Service?s Forest Inventory and Analysis (FIA) program and used by the Northern Region of the National Forest System to analyze the compliance of individual National Forests with their Standards and Guidelines. It emphasizes use of FIA data on snag density and the percentage of forest area that meets the...

  18. The value of volume and growth measurements in timber sales management of the National Forests

    NASA Technical Reports Server (NTRS)

    Lietzke, K. R.

    1977-01-01

    This paper summarizes work performed in the estimation of gross social value of timber volume and growth rate information used in making regional harvest decisions in the National Forest System. A model was developed to permit parametric analysis. The problem is formulated as one of finding optimal inventory holding patterns. Public timber management differs from other inventory holding problems in that the inventory, itself, generates value over time in providing recreational, aesthetic and environmental goods. 'Nontimber' demand estimates are inferred from past Forest Service harvest and sales levels. The solution requires a description of the harvest rates which maintain the optimum inventory level. Gross benefits of the Landsat systems are estimated by comparison with Forest Service information gathering models. Gross annual benefits are estimated to be $5.9 million for the MSS system and $7.2 million for the TM system.

  19. The value of volume and growth measurements in timber sales management of the National Forests

    NASA Technical Reports Server (NTRS)

    Lietzke, K. R.

    1977-01-01

    This paper summarizes work performed in the estimation of gross social value of timber volume and growth rate information used in making regional harvest decisions in the National Forest System. A model was developed to permit parametric analysis. The problem is formulated as one of finding optimal inventory holding patterns. Public timber management differs from other inventory holding problems in that the inventory, itself, generates value over time in providing recreational, aesthetic and environmental goods. 'Nontimber' demand estimates are inferred from past Forest Service harvest and sales levels. The solution requires a description of the harvest rates which maintain the optimum inventory level. Gross benefits of the Landsat systems are estimated by comparison with Forest Service information gathering models. Gross annual benefits are estimated to be $5.9 million for the MSS system and $7.2 million for the TM system.

  20. Credit Risk Evaluation of Power Market Players with Random Forest

    NASA Astrophysics Data System (ADS)

    Umezawa, Yasushi; Mori, Hiroyuki

    A new method is proposed for credit risk evaluation in a power market. The credit risk evaluation is to measure the bankruptcy risk of the company. The power system liberalization results in new environment that puts emphasis on the profit maximization and the risk minimization. There is a high probability that the electricity transaction causes a risk between companies. So, power market players are concerned with the risk minimization. As a management strategy, a risk index is requested to evaluate the worth of the business partner. This paper proposes a new method for evaluating the credit risk with Random Forest (RF) that makes ensemble learning for the decision tree. RF is one of efficient data mining technique in clustering data and extracting relationship between input and output data. In addition, the method of generating pseudo-measurements is proposed to improve the performance of RF. The proposed method is successfully applied to real financial data of energy utilities in the power market. A comparison is made between the proposed and the conventional methods.

  1. Evaluating climate variability and management impacts on carbon dynamics of a temperate forest using a variety of techniques

    NASA Astrophysics Data System (ADS)

    Arain, M. A.

    2015-12-01

    Climate variability, extreme weather events, forest age and management history impacts carbon sequestration in forest ecosystems. A variety of measurement techniques such as eddy covariance, dendrochronology, automatic soil CO2 chambers and remote sensing are employed fully understand forest carbon dynamics. Here, we present carbon flux measurements from 2003-2014 in a 76-year old managed temperate pine ((-Pinus strobus L.) forest, near Lake Erie in southern Ontario, Canada. Forest was partially thinned (30% tree harvested) in 1983 and 2012. The thinning in 2012 did not significantly impact carbon fluxes as post-thinning fluxes were within the range of inter-annual variability. Mean annual post-thinning (2012-2104) gross ecosystem productivity (GEP) measure by the eddy covariance technique was 1518 ± 78 g C m-2 year-1 as compared to pre-thinning (2003-2011) GEP of 1384 ± 121 g C m-2·year-1. Over the same period, mean post-thinning net ecosystem productivity (NEP) was 185 ± 75 g C m-2 year-1 as compared to post-thinning NEP of 180 ± 70 g C m-2 year-1, indicating that pre-thinning NEP was not significantly different than post-thinning NEP. Only post-thinning mean annual ecosystem respiration (Re; 1322 ± 54 g C m-2 year-1) was higher than pre-thinning Re (1195 ± 101 g C m-2 year-1). Soil CO2 efflux measurements showed similar trends. We also evaluated the impacts of climate variability and management regime on the full life cycle of the forest using annual radial tree-ring growths from 15 trees and compared them with historical climate (temperature and precipitation) data. While the annual growth rates displayed weak correlation with long-term climatic records, the growth was generally reduced during years with extreme drought (-36% of mean annual precipitation) and extreme temperature variability (±0.6 - 1.0°C). Overall, forest was more sensitive to management regime than climate variability. It showed higher growth stress during low light condition after

  2. Drought stress, growth and nonstructural carbohydrate dynamics of pine trees in a semi-arid forest.

    PubMed

    Klein, Tamir; Hoch, Günter; Yakir, Dan; Körner, Christian

    2014-09-01

    In trees exposed to prolonged drought, both carbon uptake (C source) and growth (C sink) typically decrease. This correlation raises two important questions: (i) to what degree is tree growth limited by C availability; and (ii) is growth limited by concurrent C storage (e.g., as nonstructural carbohydrates, NSC)? To test the relationships between drought, growth and C reserves, we monitored the changes in NSC levels and constructed stem growth chronologies of mature Pinus halepensis Miller trees of three drought stress levels growing in Yatir forest, Israel, at the dry distribution limit of forests. Moderately stressed and stressed trees showed 34 and 14% of the stem growth, 71 and 31% of the sap flux density, and 79 and 66% of the final needle length of healthy trees in 2012. In spite of these large reductions in growth and sap flow, both starch and soluble sugar concentrations in the branches of these trees were similar in all trees throughout the dry season (2-4% dry mass). At the same time, the root starch concentrations of moderately stressed and stressed trees were 47 and 58% of those of healthy trees, but never <2% dry mass. Our results show that all the studied trees maintain a fairly good coordination between C supply and demand, and even during prolonged drought there is more than one way for a tree to maintain a positive C balance.

  3. Texas' forests, 2008

    Treesearch

    James W. Bentley; Consuelo Brandeis; Jason A. Cooper; Christopher M. Oswalt; Sonja N. Oswalt; KaDonna Randolph

    2014-01-01

    This bulletin describes forest resources of the State of Texas at the time of the 2008 forest inventory. This bulletin addresses forest area, volume, growth, removals, mortality, forest health, timber product output, and the economy of the forest sector.

  4. [Evapotranspiration characteristics of artificial and natural forests in Liupan Mountains of Ningxia, China during growth season].

    PubMed

    Cao, Gong-xiang; Wang, Xu-fang; Xiong, Wei; Wang, Yan-hui; Yu, Peng-tao; Wang, Yun-ni; Xu, Li-hong; Li, Zhen-hua

    2013-08-01

    In order to understand the effects of the structure of forest ecosystem on the hydrological processes, a comparative study by using thermal dissipation technique and hydrological methodology was made on the evapotranspiration (ET) and its components of Larix principis-rupprechtii plantation and Pinus armandi natural forest in two adjacent stands in a small catchment Xiangshuihe of Liupan Mountains during the growth season (May-October) in 2009. Throughout the growth season, the total ET from the plantation was 518.2 mm, which accounted for 104.6% of the precipitation and was much higher than that (420.5 mm) of the natural forest. The allocation of ET in the vertical layers performed similarly between the two stands, with the order of canopy layer > herb and soil layer > shrub layer, but the ratio of each component to total ET differed significantly. The plantation consumed 0.2 and 0.9 times more water for canopy interception (19.6 mm per month) and tree transpiration (25.2 mm per month) than the natural forest, respectively. However, the transpiration from the plantation was 4.4 mm per month, and took up 23.4% of the natural forest. In contrast, the sum of soil evaporation and herbage evapotranspiration consumed 37.1 mm water per month in the plantation, which was 0.8 times higher than that in the natural forest. The ET was calculated by Penman-Monteith equation to compare the results estimated by sap flow measurements, and the values estimated by the two methods were similar.

  5. Climate, canopy disturbance, and radial growth averaging in a second-growth mixed-oak forest in West Virginia, USA

    Treesearch

    James S. Rentch; B. Desta Fekedulegn; Gary W. Miller

    2002-01-01

    This study evaluated the use of radial growth averaging as a technique of identifying canopy disturbances in a thinned 55-year-old mixed-oak stand in West Virginia. We used analysis of variance to determine the time interval (averaging period) and lag period (time between thinning and growth increase) that best captured the growth increase associated with different...

  6. Modeling Forest Biomass and Growth: Coupling Long-Term Inventory and Lidar Data

    NASA Technical Reports Server (NTRS)

    Babcock, Chad; Finley, Andrew O.; Cook, Bruce D.; Weiskittel, Andrew; Woodall, Christopher W.

    2016-01-01

    Combining spatially-explicit long-term forest inventory and remotely sensed information from Light Detection and Ranging (LiDAR) datasets through statistical models can be a powerful tool for predicting and mapping above-ground biomass (AGB) at a range of geographic scales. We present and examine a novel modeling approach to improve prediction of AGB and estimate AGB growth using LiDAR data. The proposed model accommodates temporal misalignment between field measurements and remotely sensed data-a problem pervasive in such settings-by including multiple time-indexed measurements at plot locations to estimate AGB growth. We pursue a Bayesian modeling framework that allows for appropriately complex parameter associations and uncertainty propagation through to prediction. Specifically, we identify a space-varying coefficients model to predict and map AGB and its associated growth simultaneously. The proposed model is assessed using LiDAR data acquired from NASA Goddard's LiDAR, Hyper-spectral & Thermal imager and field inventory data from the Penobscot Experimental Forest in Bradley, Maine. The proposed model outperformed the time-invariant counterpart models in predictive performance as indicated by a substantial reduction in root mean squared error. The proposed model adequately accounts for temporal misalignment through the estimation of forest AGB growth and accommodates residual spatial dependence. Results from this analysis suggest that future AGB models informed using remotely sensed data, such as LiDAR, may be improved by adapting traditional modeling frameworks to account for temporal misalignment and spatial dependence using random effects.

  7. Bat activity in thinned, unthinned, and old-growth forests in western Oregon

    USGS Publications Warehouse

    Humes, Marcia L.; Hayes, J.P.; Collopy, M.W.

    1999-01-01

    Many aspects of the influences of forest management activities on bats (Chiroptera) in the Pacific Northwest are poorly known. We compared thinned and unthinned forest stands of the same age and old-growth forest stands to determine potential differences in structure and amount of use by bats. We hypothesized that activity levels of bats would differ in stands differing in structure as a result of management history and that activity of bats would be similar in stands of similar structure. We used automated ultrasonic detectors (Anabat II) to record calls of bats in 50-100-year-old thinned and unthinned stands, and in old-growth (a?Y200 yr old) stands in the Oregon Coast Range during the summers of 1994 and 1995. Our median index of bat activity was higher in old-growth than in unthinned stands and higher in thinned than in unthinned stands. We were not able to detect a significant difference between the index of median bat activity for old-growth and thinned stands. More than 90% of identifiable passes were identified as calls from Myotis species. The 3 stand types we examined differed in certain structural characteristics such as density and size of trees, and amount of overstory and understory cover. We concluded that the structural changes caused by thinning may benefit bats by creating habitat structure in young stands that bats are able to use more effectively.

  8. Ground layer plant species turnover and beta diversity in southern-European old-growth forests.

    PubMed

    Sabatini, Francesco Maria; Burrascano, Sabina; Tuomisto, Hanna; Blasi, Carlo

    2014-01-01

    Different assembly processes may simultaneously affect local-scale variation of species composition in temperate old-growth forests. Ground layer species diversity reflects chance colonization and persistence of low-dispersal species, as well as fine-scale environmental heterogeneity. The latter depends on both purely abiotic factors, such as soil properties and topography, and factors primarily determined by overstorey structure, such as light availability. Understanding the degree to which plant diversity in old-growth forests is associated with structural heterogeneity and/or to dispersal limitation will help assessing the effectiveness of silvicultural practices that recreate old-growth patterns and structures for the conservation or restoration of plant diversity. We used a nested sampling design to assess fine-scale species turnover, i.e. the proportion of species composition that changes among sampling units, across 11 beech-dominated old-growth forests in Southern Europe. For each stand, we also measured a wide range of environmental and structural variables that might explain ground layer species turnover. Our aim was to quantify the relative importance of dispersal limitation in comparison to that of stand structural heterogeneity while controlling for other sources of environmental heterogeneity. For this purpose, we used multiple regression on distance matrices at the within-stand extent, and mixed effect models at the extent of the whole dataset. Species turnover was best predicted by structural and environmental heterogeneity, especially by differences in light availability and in topsoil nutrient concentration and texture. Spatial distances were significant only in four out of eleven stands with a relatively low explanatory power. This suggests that structural heterogeneity is a more important driver of local-scale ground layer species turnover than dispersal limitation in southern European old-growth beech forests.

  9. Disturbance legacies and climate jointly drive tree growth and mortality in an intensively studied boreal forest

    SciTech Connect

    Bond-Lamberty, Benjamin; Rocha, Adrian; Calvin, Katherine V.; Holmes, Bruce; Wang, Chuankuan; Goulden, Michael L.

    2014-01-01

    How will regional growth and mortality change with even relatively small climate shifts, even independent of catastrophic disturbances? This question is particularly acute for the North American boreal forest, which is carbon-dense and subject The goals of this study were to combine dendrochronological sampling, inventory records, and machine-learning algorithms to understand how tree growth and death have changed at one highly studied site (Northern Old Black Spruce, NOBS) in the central Canadian boreal forest. Over the 1999-2012 inventory period, mean DBH increased even as stand density and basal area declined significantly from 41.3 to 37.5 m2 ha-1. Tree mortality averaged 1.4±0.6% yr-1, with most mortality occurring in medium-sized trees. A combined tree ring chronology constructed from 2001, 2004, and 2012 sampling showed several periods of extreme growth depression, with increased mortality lagging depressed growth by ~5 years. Minimum and maximum air temperatures exerted a negative influence on tree growth, while precipitation and climate moisture index had a positive effect; both current- and previous-year data exerted significant effects. Models based on these variables explained 23-44% of the ring-width variability. There have been at least one, and probably two, significant recruitment episodes since stand initiation, and we infer that past climate extremes led to significant NOBS mortality still visible in the current forest structure. These results imply that a combination of successional and demographic processes, along with mortality driven by abiotic factors, continue to affect the stand, with significant implications for our understanding of previous work at NOBS and the sustainable management of regional forests.

  10. Ground Layer Plant Species Turnover and Beta Diversity in Southern-European Old-Growth Forests

    PubMed Central

    Sabatini, Francesco Maria; Burrascano, Sabina; Tuomisto, Hanna; Blasi, Carlo

    2014-01-01

    Different assembly processes may simultaneously affect local-scale variation of species composition in temperate old-growth forests. Ground layer species diversity reflects chance colonization and persistence of low-dispersal species, as well as fine-scale environmental heterogeneity. The latter depends on both purely abiotic factors, such as soil properties and topography, and factors primarily determined by overstorey structure, such as light availability. Understanding the degree to which plant diversity in old-growth forests is associated with structural heterogeneity and/or to dispersal limitation will help assessing the effectiveness of silvicultural practices that recreate old-growth patterns and structures for the conservation or restoration of plant diversity. We used a nested sampling design to assess fine-scale species turnover, i.e. the proportion of species composition that changes among sampling units, across 11 beech-dominated old-growth forests in Southern Europe. For each stand, we also measured a wide range of environmental and structural variables that might explain ground layer species turnover. Our aim was to quantify the relative importance of dispersal limitation in comparison to that of stand structural heterogeneity while controlling for other sources of environmental heterogeneity. For this purpose, we used multiple regression on distance matrices at the within-stand extent, and mixed effect models at the extent of the whole dataset. Species turnover was best predicted by structural and environmental heterogeneity, especially by differences in light availability and in topsoil nutrient concentration and texture. Spatial distances were significant only in four out of eleven stands with a relatively low explanatory power. This suggests that structural heterogeneity is a more important driver of local-scale ground layer species turnover than dispersal limitation in southern European old-growth beech forests. PMID:24748155

  11. Temperature and rainfall strongly drive temporal growth variation in Asian tropical forest trees.

    PubMed

    Vlam, Mart; Baker, Patrick J; Bunyavejchewin, Sarayudh; Zuidema, Pieter A

    2014-04-01

    Climate change effects on growth rates of tropical trees may lead to alterations in carbon cycling of carbon-rich tropical forests. However, climate sensitivity of broad-leaved lowland tropical trees is poorly understood. Dendrochronology (tree-ring analysis) provides a powerful tool to study the relationship between tropical tree growth and annual climate variability. We aimed to establish climate-growth relationships for five annual-ring forming tree species, using ring-width data from 459 canopy and understory trees from a seasonal tropical forest in western Thailand. Based on 183/459 trees, chronologies with total lengths between 29 and 62 years were produced for four out of five species. Bootstrapped correlation analysis revealed that climate-growth responses were similar among these four species. Growth was significantly negatively correlated with current-year maximum and minimum temperatures, and positively correlated with dry-season precipitation levels. Negative correlations between growth and temperature may be attributed to a positive relationship between temperature and autotrophic respiration rates. The positive relationship between growth and dry-season precipitation levels likely reflects the strong water demand during leaf flush. Mixed-effect models yielded results that were consistent across species: a negative effect of current wet-season maximum temperatures on growth, but also additive positive effects of, for example, prior dry-season maximum temperatures. Our analyses showed that annual growth variability in tropical trees is determined by a combination of both temperature and precipitation variability. With rising temperature, the predominantly negative relationship between temperature and growth may imply decreasing growth rates of tropical trees as a result of global warming.

  12. Long-term growth trends and time series of elemental wood composition from two old-growth forests - natural versus anthropogenic influences

    NASA Astrophysics Data System (ADS)

    Scharnweber, Tobias; van der Maaten, Ernst; Heinrich, Ingo; Buras, Allan; van der Maaten Theunissen, Marieke; Wilmking, Martin

    2014-05-01

    In contrast to extreme environments with low human impact, where often one specific (climatic) factor is limiting tree growth, dendrochronological research in the temperate zone has to cope with a wide variety of climatic and non-climatic drivers. Sophisticated statistical tools, like various detrending and filtering techniques, allow for a rather precise analysis of high-frequency (annual) climate-growth relationships. However, as almost all forests in the temperate zone are to some degree influenced by human activities, it is difficult to separate anthropogenic from climatic influence on the lower time-frequencies of decades to centuries. Footprints of human activity in time series of tree-ring parameters might be caused directly through forest utilization (logging) or indirectly through environmental changes such as eutrophication or atmospheric pollution. The former can be elucidated by traditional dendrochronological techniques based on ring parameters; evaluation of the latter requires additional proxies such as dendrochemical data. For the interpretation of long-term trends and the calibration of tree-ring based reconstructions it is therefore necessary to study tree growth in as undisturbed forest environments as possible. Comparison with dendrochronological time series from managed forest might then allow separation of climatic- from anthropogenic signals. Here, we present long-term growth trends for the broadleaved tree species common beech, pedunculate oak and sycamore maple, from two protected old-growth forests in northern Germany (one with a documented last logging activity dating back to 1527), and compare those with well-replicated regional chronologies from other, mostly managed forests. Our results indicate that several low frequency trends that can be found in many regional chronologies are likely caused by synchronous periods of heavy loggings as for example during the years following World War II, and do not relate to climatic drivers. In

  13. Domination of hillslope denudation by tree uprooting in an old-growth forest

    NASA Astrophysics Data System (ADS)

    Phillips, Jonathan D.; Šamonil, Pavel; Pawlik, Łukasz; Trochta, Jan; Daněk, Pavel

    2017-01-01

    Razula forest preserve in the Carpathian Mountains of the Czech Republic is an unmanaged forest that has not been logged or otherwise anthropically disturbed for at least 83 years, preceded by only infrequent selective logging. We examined this 25 ha area to determine the dominant geomorphological processes on the hillslope. Tree uprooting displaces about 2.9 m3 of soil and regolith per year, representing about 1.5 uprooted trees ha- 1 yr- 1, based on forest inventory records dating back to 1972, and contemporary measurements of displaced soil and pit-mound topography resulting from uprooting. Pits and mounds occupy > 14% of the ground surface. Despite typical slope gradients of 0.05 mm- 1, and up to 0.41, little evidence of mass wasting (e.g., slump or flow scars or deposits, colluvial deposits) was noted in the field, except in association with pit-mound pairs. Small avalanche and ravel features are common on the upslope side of uproot pits. Surface runoff features were rare and poorly connected, but do include stemwash erosion associated with stemflow. No rills or channels were found above the valley bottom area, and only small, localized areas of erosion and forest litter debris indicating overland flow. Where these features occurred, they either disappeared a short distance downslope (indicating infiltration), or indicate flow into tree throw pits. Surface erosion is also inhibited by surface armoring of coarse rock fragments associated with uprooting, as well as by the nearly complete vegetation and litter cover. These results show that the combination of direct and indirect impacts of tree uprooting can dominate slope processes in old-growth, unmanaged forests. The greater observed expression of different hillslope processes in adjacent managed forests (where tree uprooting dynamics are blocked by management activities) suggests that human interventions can change the slope process regime in forest ecosystems.

  14. Evaluation of directional normalization methods for Landsat TM/ETM+ over primary Amazonian lowland forests

    NASA Astrophysics Data System (ADS)

    Van doninck, Jasper; Tuomisto, Hanna

    2017-06-01

    Biodiversity mapping in extensive tropical forest areas poses a major challenge for the interpretation of Landsat images, because floristically clearly distinct forest types may show little difference in reflectance. In such cases, the effects of the bidirectional reflection distribution function (BRDF) can be sufficiently strong to cause erroneous image interpretation and classification. Since the opening of the Landsat archive in 2008, several BRDF normalization methods for Landsat have been developed. The simplest of these consist of an empirical view angle normalization, whereas more complex approaches apply the semi-empirical Ross-Li BRDF model and the MODIS MCD43-series of products to normalize directional Landsat reflectance to standard view and solar angles. Here we quantify the effect of surface anisotropy on Landsat TM/ETM+ images over old-growth Amazonian forests, and evaluate five angular normalization approaches. Even for the narrow swath of the Landsat sensors, we observed directional effects in all spectral bands. Those normalization methods that are based on removing the surface reflectance gradient as observed in each image were adequate to normalize TM/ETM+ imagery to nadir viewing, but were less suitable for multitemporal analysis when the solar vector varied strongly among images. Approaches based on the MODIS BRDF model parameters successfully reduced directional effects in the visible bands, but removed only half of the systematic errors in the infrared bands. The best results were obtained when the semi-empirical BRDF model was calibrated using pairs of Landsat observation. This method produces a single set of BRDF parameters, which can then be used to operationally normalize Landsat TM/ETM+ imagery over Amazonian forests to nadir viewing and a standard solar configuration.

  15. Foliar and ecosystem respiration in an old-growth tropical rain forest.

    PubMed

    Cavaleri, Molly A; Oberbauer, Steven F; Ryan, Michael G

    2008-04-01

    Foliar respiration is a major component of ecosystem respiration, yet extrapolations are often uncertain in tropical forests because of indirect estimates of leaf area index (LAI). A portable tower was used to directly measure LAI and night-time foliar respiration from 52 vertical transects throughout an old-growth tropical rain forest in Costa Rica. In this study, we (1) explored the effects of structural, functional and environmental variables on foliar respiration; (2) extrapolated foliar respiration to the ecosystem; and (3) estimated ecosystem respiration. Foliar respiration temperature response was constant within plant functional group, and foliar morphology drove much of the within-canopy variability in respiration and foliar nutrients. Foliar respiration per unit ground area was 3.5 +/- 0.2 micromol CO2 m(-2) s(-1), and ecosystem respiration was 9.4 +/- 0.5 micromol CO2 m(-2) s(-1)[soil = 41%; foliage = 37%; woody = 14%; coarse woody debris (CWD) = 7%]. When modelled with El Niño Southern Oscillation (ENSO) year temperatures, foliar respiration was 9% greater than when modelled with temperatures from a normal year, which is in the range of carbon sink versus source behaviour for this forest. Our ecosystem respiration estimate from component fluxes was 33% greater than night-time net ecosystem exchange for the same forest, suggesting that studies reporting a large carbon sink for tropical rain forests based solely on eddy flux measurements may be in error.

  16. No growth stimulation of Canada's boreal forest under half-century of combined warming and CO2 fertilization.

    PubMed

    Girardin, Martin P; Bouriaud, Olivier; Hogg, Edward H; Kurz, Werner; Zimmermann, Niklaus E; Metsaranta, Juha M; de Jong, Rogier; Frank, David C; Esper, Jan; Büntgen, Ulf; Guo, Xiao Jing; Bhatti, Jagtar

    2016-12-27

    Considerable evidence exists that current global temperatures are higher than at any time during the past millennium. However, the long-term impacts of rising temperatures and associated shifts in the hydrological cycle on the productivity of ecosystems remain poorly understood for mid to high northern latitudes. Here, we quantify species-specific spatiotemporal variability in terrestrial aboveground biomass stem growth across Canada's boreal forests from 1950 to the present. We use 873 newly developed tree-ring chronologies from Canada's National Forest Inventory, representing an unprecedented degree of sampling standardization for a large-scale dendrochronological study. We find significant regional- and species-related trends in growth, but the positive and negative trends compensate each other to yield no strong overall trend in forest growth when averaged across the Canadian boreal forest. The spatial patterns of growth trends identified in our analysis were to some extent coherent with trends estimated by remote sensing, but there are wide areas where remote-sensing information did not match the forest growth trends. Quantifications of tree growth variability as a function of climate factors and atmospheric CO2 concentration reveal strong negative temperature and positive moisture controls on spatial patterns of tree growth rates, emphasizing the ecological sensitivity to regime shifts in the hydrological cycle. An enhanced dependence of forest growth on soil moisture during the late-20th century coincides with a rapid rise in summer temperatures and occurs despite potential compensating effects from increased atmospheric CO2 concentration.

  17. No growth stimulation of Canada’s boreal forest under half-century of combined warming and CO2 fertilization

    PubMed Central

    Girardin, Martin P.; Hogg, Edward H.; Kurz, Werner; Zimmermann, Niklaus E.; Metsaranta, Juha M.; de Jong, Rogier; Frank, David C.; Esper, Jan; Büntgen, Ulf; Guo, Xiao Jing; Bhatti, Jagtar

    2016-01-01

    Considerable evidence exists that current global temperatures are higher than at any time during the past millennium. However, the long-term impacts of rising temperatures and associated shifts in the hydrological cycle on the productivity of ecosystems remain poorly understood for mid to high northern latitudes. Here, we quantify species-specific spatiotemporal variability in terrestrial aboveground biomass stem growth across Canada’s boreal forests from 1950 to the present. We use 873 newly developed tree-ring chronologies from Canada’s National Forest Inventory, representing an unprecedented degree of sampling standardization for a large-scale dendrochronological study. We find significant regional- and species-related trends in growth, but the positive and negative trends compensate each other to yield no strong overall trend in forest growth when averaged across the Canadian boreal forest. The spatial patterns of growth trends identified in our analysis were to some extent coherent with trends estimated by remote sensing, but there are wide areas where remote-sensing information did not match the forest growth trends. Quantifications of tree growth variability as a function of climate factors and atmospheric CO2 concentration reveal strong negative temperature and positive moisture controls on spatial patterns of tree growth rates, emphasizing the ecological sensitivity to regime shifts in the hydrological cycle. An enhanced dependence of forest growth on soil moisture during the late-20th century coincides with a rapid rise in summer temperatures and occurs despite potential compensating effects from increased atmospheric CO2 concentration. PMID:27956624

  18. Large Impacts of Climatic Warming on Growth of Boreal Forests since 1960

    PubMed Central

    Kauppi, Pekka E.; Posch, Maximilian; Pirinen, Pentti

    2014-01-01

    Boreal forests are sensitive to climatic warming, because low temperatures hold back ecosystem processes, such as the mobilization of nitrogen in soils. A greening of the boreal landscape has been observed using remote sensing, and the seasonal amplitude of CO2 in the northern hemisphere has increased, indicating warming effects on ecosystem productivity. However, field observations on responses of ecosystem productivity have been lacking on a large sub-biome scale. Here we report a significant increase in the annual growth of boreal forests in Finland in response to climatic warming, especially since 1990. This finding is obtained by linking meteorological records and forest inventory data on an area between 60° and 70° northern latitude. An additional increase in growth has occurred in response to changes in other drivers, such as forest management, nitrogen deposition and/or CO2 concentration. A similar warming impact can be expected in the entire boreal zone, where warming takes place. Given the large size of the boreal biome – more than ten million km2– important climate feedbacks are at stake, such as the future carbon balance, transpiration and albedo. PMID:25383552

  19. Large impacts of climatic warming on growth of boreal forests since 1960.

    PubMed

    Kauppi, Pekka E; Posch, Maximilian; Pirinen, Pentti

    2014-01-01

    Boreal forests are sensitive to climatic warming, because low temperatures hold back ecosystem processes, such as the mobilization of nitrogen in soils. A greening of the boreal landscape has been observed using remote sensing, and the seasonal amplitude of CO2 in the northern hemisphere has increased, indicating warming effects on ecosystem productivity. However, field observations on responses of ecosystem productivity have been lacking on a large sub-biome scale. Here we report a significant increase in the annual growth of boreal forests in Finland in response to climatic warming, especially since 1990. This finding is obtained by linking meteorological records and forest inventory data on an area between 60° and 70° northern latitude. An additional increase in growth has occurred in response to changes in other drivers, such as forest management, nitrogen deposition and/or CO2 concentration. A similar warming impact can be expected in the entire boreal zone, where warming takes place. Given the large size of the boreal biome - more than ten million km2- important climate feedbacks are at stake, such as the future carbon balance, transpiration and albedo.

  20. Seasonal carbon fluxes for an old-growth temperate forest inferred from carbonyl sulphide

    NASA Astrophysics Data System (ADS)

    Rastogi, Bharat; Jiang, Yueyang; Berkelhammer, Maxwell; Wharton, Sonia; Noone, David; Still, Christopher

    2017-04-01

    Characterizing and quantifying the processes that control terrestrial ecosystem exchanges of carbon and water are critical for understanding how forested ecosystems respond to a changing climate. A small but increasing number of studies has identified carbonyl sulfide (OCS) as a potential tracer of canopy photosynthesis and stomatal function. Here we present seasonal fluxes of OCS from a 60m tall old-growth temperate forest. An off-axis integrated cavity output spectroscopy analyzer (Los Gatos Research Inc.) was deployed at the Wind River Experimental Forest in Washington (45.8205°N, 121.9519°W) in 2014 and 2015. GPP (Gross Primary Production) is inferred from OCS fluxes and compared with estimates derived from measurements of NEE (Net Ecosystem Exchange) from eddy flux data as well as GPP predictions using a process based model. Our findings seek to resolve scientific questions regarding ecosystem carbon exchange from tall old growth forests, which have a complicated vertical leaf area structure, high above ground biomass and amount and aerial cover of epiphytic vegetation. Estimates of canopy conductance calculated using tower flux data are also combined with measurements of stable isotopologues of CO2 to infer emergent ecosystem properties such as canopy ci/ca and water use efficiency.

  1. Improved and large area single-walled carbon nanotube forest growth by controlling the gas flow direction.

    PubMed

    Yasuda, Satoshi; Futaba, Don N; Yamada, Takeo; Satou, Junichi; Shibuya, Akiyoshi; Takai, Hirokazu; Arakawa, Kouhei; Yumura, Motoo; Hata, Kenji

    2009-12-22

    A gas shower system was introduced to improve the growth of single-walled carbon nanotube (SWNT) forests by controlling the gas flow direction. Delivery of gases from the top of the forest enabled direct and precise supply of ethylene and water vapor to the Fe catalysts. As such, this approach solved one of the limiting factors of water-assisted chemical vapor deposition method (CVD), that is, delivery of the very small optimum water level to the catalysts. Consequently, this approach improved SWNT forests growth stability, uniformity, reproducibility, carbon efficiency (32%), and catalyst lifetime. With this improved growth, we could synthesize a 1 cm tall forest with 1 x 1 cm size. Also we employed this approach to grow an A4 size SWNT forest to highlight the scalability of water-assisted CVD.

  2. Response of old-growth conifers to reduction in stand density in western Oregon forests

    USGS Publications Warehouse

    Latham, P.; Tappeiner, J. C.

    2002-01-01

    The positive growth response of healthy young trees to density reduction is well known. In contrast, large old trees are usually thought to be intrinsically limited in their ability to respond to increased growing space; therefore, density reduction is seldom used in stands of old-growth trees. We tested the null hypothesis that old-growth trees are incapable of responding with increased growth following density reduction. The diameter growth response of 271 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), ponderosa pine (Pinus ponderosa Dougl. ex Laws) and sugar pine (Pinus lambertiana Dougl.) trees ranging in age from 158 to 650 years was examined 20 to 50 years after density reduction. Density reduction involved either light thinning with removal of less vigorous trees, or shelterwood treatments in which overstory trees were not removed. Ratios of basal area growth after treatment to basal area growth before treatment, and several other measures of growth, all indicated that the old trees sometimes benefited and were not harmed by density reduction. Growth increased by 10% or more for 68% of the trees in treated stands, and nearly 30% of trees increased growth by over 50%. This growth response persisted for at least 20 years. During this 20-year period, only three trees in treated stands (1.5%) exhibited a rapid decrease in growth, whereas growth decreased in 64% of trees in untreated stands. The length of time before a growth response to density reduction occurred varied from 5 to 25 years, with the greatest growth response often occurring 20 to 25 years after treatment. These results have important implications both for the basic biology of aging in woody plants as well as for silvicultural practices in forests with old-growth trees.

  3. [Characteristics of CO₂ flux in an old growth mixed forest in Tianmu Mountain, Zhejiang, China].

    PubMed

    Niu, Xiao-dong; Jiang, Hong; Zhang, Jin-meng; Fang, Cheng-yuan; Chen, Xiao-feng; Sun, Heng

    2016-01-01

    The old-growth, multiple ages, multispecies natural forest has played an important role in terrestrial ecosystem dynamics model and the global carbon budget. However, carbon fluxes of old forests in subtropical regions are rarely reported in China. In the present study, the CO₂ flux of an old-growth subtropical evergreen and deciduous broad-leaved mixed forest was observed using eddy covariance technique in Tianmu Mountain of Zhejiang Province. Based on the data sets which were observed from July 2013 to June 2014, the variations of net ecosystem exchange (NEE), eco-system respiration (Re), and gross ecosystem exchange (GEE) were analyzed. The results showed that during the study period, the monthly NEE all had a negative value (acted as a carbon sink) except for December and February (acted as a carbon source). The average monthly NEE was -61.52 g C · m⁻², the monthly carbon sequestration showed a double-peak curve and the maximum carbon sink was -149.40 g C · m⁻², which occurred in June while the maximum carbon source was 23.45 g C · m⁻², which occurred in February. The maximum of monthly mean CO₂ flux occurred in June with a value of -0.98 mg · m⁻² · s⁻¹, while the minimum value occurred in December with a value of -0.35 mg · m⁻² · s⁻¹. The NEE at the time point of positive and negative conversion had typical seasonal characteristics. The yearly NEE, Re, and GEE were -738.18, 931.05 and -1669.23 g C · m⁻², respectively. Compared with other forest ecosystems located at the similar latitude, the carbon fixation of the old-growth forest was larger, likely due to its complicated structure within the canopy and the presence of young-growth regeneration and successional stands. This showed that other than in carbon neutral, old-growth forests of Tianmu Mountain in subtropical China had a strong capability in carbon sequestration.

  4. Growth responses of trees and understory plants to nitrogen fertilization in a subtropical forest in China

    NASA Astrophysics Data System (ADS)

    Tian, Di; Li, Peng; Fang, Wenjing; Xu, Jun; Luo, Yongkai; Yan, Zhengbing; Zhu, Biao; Wang, Jingjing; Xu, Xiaoniu; Fang, Jingyun

    2017-07-01

    Reactive nitrogen (N) increase in the biosphere has been a noteworthy aspect of global change, producing considerable ecological effects on the functioning and dynamics of the terrestrial ecosystems. A number of observational studies have explored responses of plants to experimentally simulated N enrichment in boreal and temperate forests. Here we investigate how the dominant trees and different understory plants respond to experimental N enrichment in a subtropical forest in China. We conducted a 3.4-year N fertilization experiment in an old-aged subtropical evergreen broad-leaved forest in eastern China with three treatment levels applied to nine 20 m × 20 m plots and replicated in three blocks. We divided the plants into trees, saplings, shrubs (including tree seedlings), and ground-cover plants (ferns) according to the growth forms, and then measured the absolute and relative basal area increments of trees and saplings and the aboveground biomass of understory shrubs and ferns. We further grouped individuals of the dominant tree species, Castanopsis eyrei, into three size classes to investigate their respective growth responses to the N fertilization. Our results showed that the plot-averaged absolute and relative growth rates of basal area and aboveground biomass of trees were not affected by N fertilization. Across the individuals of C. eyrei, the small trees with a DBH (diameter at breast height) of 5-10 cm declined by 66.4 and 59.5 %, respectively, in N50 (50 kg N ha-1 yr-1) and N100 fertilized plots (100 kg N ha-1 yr-1), while the growth of median and large trees with a DBH of > 10 cm did not significantly change with the N fertilization. The growth rate of small trees, saplings, and the aboveground biomass of understory shrubs and ground-cover ferns decreased significantly in the N-fertilized plots. Our findings suggested that N might not be a limiting nutrient in this mature subtropical forest, and that the limitation of other nutrients in the forest

  5. A New Model for Size-Dependent Tree Growth in Forests.

    PubMed

    Ishihara, Masae Iwamoto; Konno, Yasuo; Umeki, Kiyoshi; Ohno, Yasuyuki; Kikuzawa, Kihachiro

    2016-01-01

    Tree growth, especially diameter growth of tree stems, is an important issue for understanding the productivity and dynamics of forest stands. Metabolic scaling theory predicted that the 2/3 power of stem diameter at a certain time is a linear function of the 2/3 power of the initial diameter and that the diameter growth rate scales to the 1/3 power of the initial diameter. We tested these predictions of the metabolic scaling theory for 11 Japanese secondary forests at various growth stages. The predictions were not supported by the data, especially in younger stands. Alternatively, we proposed a new theoretical model for stem diameter growth on the basis of six assumptions. All these assumptions were supported by the data. The model produced a nearly linear to curvilinear relationship between the 2/3 power of stem diameters at two different times. It also fitted well to the curvilinear relationship between diameter growth rate and the initial diameter. Our model fitted better than the metabolic scaling theory, suggesting the importance of asymmetric competition among trees, which has not been incorporated in the metabolic scaling theory.

  6. A New Model for Size-Dependent Tree Growth in Forests

    PubMed Central

    Konno, Yasuo; Umeki, Kiyoshi; Ohno, Yasuyuki

    2016-01-01

    Tree growth, especially diameter growth of tree stems, is an important issue for understanding the productivity and dynamics of forest stands. Metabolic scaling theory predicted that the 2/3 power of stem diameter at a certain time is a linear function of the 2/3 power of the initial diameter and that the diameter growth rate scales to the 1/3 power of the initial diameter. We tested these predictions of the metabolic scaling theory for 11 Japanese secondary forests at various growth stages. The predictions were not supported by the data, especially in younger stands. Alternatively, we proposed a new theoretical model for stem diameter growth on the basis of six assumptions. All these assumptions were supported by the data. The model produced a nearly linear to curvilinear relationship between the 2/3 power of stem diameters at two different times. It also fitted well to the curvilinear relationship between diameter growth rate and the initial diameter. Our model fitted better than the metabolic scaling theory, suggesting the importance of asymmetric competition among trees, which has not been incorporated in the metabolic scaling theory. PMID:27035709

  7. Growth strategies and threshold responses to water deficit modulate effects of warming on tree seedlings from forest to alpine

    USGS Publications Warehouse

    Lazarus, Brynne E.; Castanha, Cristina; Germino, Matthew; Kueppers, Lara M.; Moyes, Andrew B.

    2017-01-01

    1.Predictions of upslope range shifts for tree species with warming are based on assumptions of moisture stress at lower elevation limits and low temperature stress at high elevation limits. However, recent studies have shown that warming can reduce tree seedling establishment across the entire gradient from subalpine forest to alpine via moisture limitation. Warming effects also vary with species, potentially resulting in community shifts in high elevation forests. 2.We examined the growth and physiology underlying effects of warming on seedling demographic patterns. We evaluated dry mass (DM), root length, allocation above- and belowground, and relative growth rate (RGR) of whole seedlings, and their ability to avoid or endure water stress via water-use efficiency and resisting turgor loss, for Pinus flexilis, Picea engelmannii and Pinus contorta seeded below, at, and above treeline in experimentally warmed, watered, and control plots in the Rocky Mountains, USA. We expected that growth and allocation responses to warming would relate to moisture status and that variation in drought tolerance traits would explain species differences in survival rates. 3.Across treatments and elevations, seedlings of all species had weak turgor-loss resistance, and growth was marginal with negative RGR in the first growth phase (-0.01 to -0.04 g/g/d). Growth was correlated with soil moisture, particularly in the relatively small-seeded P. contorta and P. engelmannii. P. flexilis, known to have the highest survivorship, attained the greatest DM and longest root but was also the slowest growing and most water-use-efficient. This was likely due to its greater reliance on seed reserves. Seedlings developed 15% less total DM, 25% less root DM, and 11% shorter roots in heated compared to unheated plots. Higher temperatures slightly increased DM, root length and RGR where soils were wettest, but more strongly decreased these variables under drier conditions. 4.Synthesis: The surprising

  8. Vertebral degenerative disc disease severity evaluation using random forest classification

    NASA Astrophysics Data System (ADS)

    Munoz, Hector E.; Yao, Jianhua; Burns, Joseph E.; Pham, Yasuyuki; Stieger, James; Summers, Ronald M.

    2014-03-01

    Degenerative disc disease (DDD) develops in the spine as vertebral discs degenerate and osseous excrescences or outgrowths naturally form to restabilize unstable segments of the spine. These osseous excrescences, or osteophytes, may progress or stabilize in size as the spine reaches a new equilibrium point. We have previously created a CAD system that detects DDD. This paper presents a new system to determine the severity of DDD of individual vertebral levels. This will be useful to monitor the progress of developing DDD, as rapid growth may indicate that there is a greater stabilization problem that should be addressed. The existing DDD CAD system extracts the spine from CT images and segments the cortical shell of individual levels with a dual-surface model. The cortical shell is unwrapped, and is analyzed to detect the hyperdense regions of DDD. Three radiologists scored the severity of DDD of each disc space of 46 CT scans. Radiologists' scores and features generated from CAD detections were used to train a random forest classifier. The classifier then assessed the severity of DDD at each vertebral disc level. The agreement between the computer severity score and the average radiologist's score had a quadratic weighted Cohen's kappa of 0.64.

  9. Patterns of mortality in an old-growth mixed-conifer forest of the Southern Sierra Nevada, California

    Treesearch

    Thomas F. Smith; David M. Rizzo; Malcolm North

    2005-01-01

    Mortality patterns in an old-growth, mixed-conifer forest, in the absence of wildfire, were investigated at the Teakettle Experimental Forest from 2000 to 2002. We tested the hypothesis that after a century of fire suppression, pathogen- and insect-associated mortality (between episodic droughts) would be significantly greater on ingrowth trees (i.e., smaller-diameter...

  10. Tree seedling growth and mortality responses to manipulations of calcium and aluminum in a northern hardwood forest

    Treesearch

    Richard K. Kobe; Gene E. Likens; Christopher Eagar

    2002-01-01

    To assess potential forest compositional responses to exchangeable soil calcium (Caexch) and aluminum (Alexch), we characterized light-dependent growth and mortality of tree seedlings under amendments of CaCl2 and AlCl3 at Hubbard Brook Experimental Forest (HBEF), New Hampshire...

  11. Effects of high- and low-intensity fires on soil properties and plant growth in a Bolivian dry forest

    Treesearch

    Deborah K. Kennard; H.L. Gholz

    2001-01-01

    We compared soil nutrient availabiiity and soil physical properties among four treatments (high-intensity fire, low- intensity fire, plant removal, and harvesting gap) and a control (intact forest understory) over a period of 18 months in a tropical dry forest in Bolivia. The effect of treatments on plant growth was tested using a shade intolerant tree species (

  12. Regeneration in windthrow areas in hemiboreal forests: the influence of microsite on the height growths of different tree species

    Treesearch

    F. Vodde; K. Jõgiste; L. Gruson; T. Ilisson; K. Köster; J.A. Stanturf

    2010-01-01

    Natural regeneration of windthrow areas is an important issue when planning forestry measures after forest disturbances. Seedling recruitment was investigated in storm-damaged hemiboreal mixed forests in eastern Estonia. The establishment and growth of seedlings from natural regeneration was registered for tree species in soil pits and in mounds of uprooted trees in...

  13. Managing heart rot in live trees for wildlife habitat in young-growth forests of coastal Alaska

    Treesearch

    Paul E. Hennon; Robin L. Mulvey

    2014-01-01

    Stem decays of living trees, known also as heart rots, are essential elements of wildlife habitat, especially for cavity-nesting birds and mammals. Stem decays are common features of old-growth forests of coastal Alaska, but are generally absent in young, managed forests. We offer several strategies for maintaining or restoring fungal stem decay in these managed...

  14. Stand and cohort structures of old-growth Pinus resinosa-dominated forests of northern Minnesota, USA

    Treesearch

    Shawn Fraver; Brian J. Palik

    2012-01-01

    The wide range of stand and age-cohort structures in these old-growth P. resinosa stands depicts pre-settlement forests more complex than those of the single-cohort, post-stand-replacing-fire model that has guided regional forest management. Within-stand patchiness of cohort age structures implies disturbances operating at scales smaller than...

  15. Effects of soil compaction on residual stand growth in central Appalachian hardwood forest: a preliminary case study

    Treesearch

    Jingxin Wang; Chris LeDoux; Michael Vanderberg; Li Yaoxiang

    2006-01-01

    A preliminary study that quantified the impacts of soil compaction on residual tree growth associated with ground-based skidding traffic intensity and turn payload size was investigated in the central Appalachian hardwood forest. The field study was carried out on a 20-acre tract of the West Virginia University Research Forest. Skid trails were laid out in 170' -...

  16. Effects of tree size and spatial distribution on growth of ponderosa pine forests under alternative management scenarios

    Treesearch

    C.W. Woodall; C.E. Fiedler; R.E. McRoberts

    2009-01-01

    Forest ecosystems may be actively managed toward heterogeneous stand structures to provide both economic (e.g., wood production and carbon credits) and environmental benefits (e.g., invasive pest resistance). In order to facilitate wider adoption of possibly more sustainable forest stand structures, defining growth expectations among alternative management scenarios is...

  17. Possibilities and limitations of using historic provenance tests to infer forest species growth responses to climate change

    Treesearch

    Laura P. Leites; Gerald E. Rehfeldt; Andrew P. Robinson; Nicholas L. Crookston; Barry Jaquish

    2012-01-01

    Under projected changes in global climate, the growth and survival of existing forests will depend on their ability to adjust physiologically in response to environmental change. Quantifying their capacity to adjust and whether the response is species- or population-specific is important to guide forest management strategies. New analyses of historic provenance tests...

  18. Stand Dynamics in an Old-Growth Hardwood Forest in Southern Illinois, USA

    Treesearch

    James J. Zaczek; John W. Groninger; J. W. Van Sambeek

    2002-01-01

    Kaskaskia Woods, a 7.4-ha old-growth hardwood forest in southern Illinois, USA, has been managed as a natural area and protected from disturbance since 1933. In 1935, eight 0.1-ha plots were installed and all trees 4 cm dbh or larger were tagged and inventoried. Trees were remeasured for survival, ingrowth (new trees >4 cm), and diameter (dbh) in 1940, 1958, 1965,...

  19. A compendium of forest growth and yield simulators for the Pacific coast states

    Treesearch

    Martin W. Ritchie

    1999-01-01

    This manuscript provides information needed for the user to access current information about forest growth and yield simulators. Ultimately, the best source of information for any simulator is the user’s guide and the sage advice of those who built the simulator. In some instances, these people are easy to find and are willing to provide all the support for the program...

  20. Ground cover in old-growth forests of the central hardwood region

    Treesearch

    Martin A. Spetich; Stephen R. Shifley; George R. Parker; Felix, Jr. Ponder

    1997-01-01

    Differences in ground cover (percent cover of litter, percent cover of vegetation and litter weight) in old-growth forests across this region are not well understood. We initiated a long-term study in a three-state region to enhance knowledge in this area. We present baseline results for ground cover and compare these data across productivity regions. Thirty 0.25-ac (0...

  1. The effect of advance growth on ponderosa pine seedling mortality at Challenge Experimental Forest

    Treesearch

    Dale O. Hall

    1963-01-01

    In seed-tree cuttings at Challenge Experimental Forest, preliminary data show that as advance-growth stocking (20 inches in d.b.h. or less ) increased from 11 t o 49 square feet, seedling mortality increased from 4 to 32 percent (based on stocked mil-acre plots). A comparable increase in the stocking of seed trees over 20 inches in d .b.h. did not increase mortality....

  2. Xylem traits, leaf longevity and growth phenology predict growth and mortality response to defoliation in northern temperate forests.

    PubMed

    Foster, Jane R

    2017-09-01

    Defoliation outbreaks are biological disturbances that alter tree growth and mortality in temperate forests. Trees respond to defoliation in many ways; some recover rapidly, while others decline gradually or die. Functional traits such as xylem anatomy, growth phenology or non-structural carbohydrate (NSC) storage could explain these responses, but idiosyncratic measures used by defoliation studies have frustrated efforts to generalize among species. Here, I test for functional differences with published growth and mortality data from 37 studies, including 24 tree species and 11 defoliators from North America and Eurasia. I synthesized data into standardized variables suitable for numerical models and used linear mixed-effects models to test the hypotheses that responses to defoliation vary among species and functional groups. Standardized data show that defoliation responses vary in shape and degree. Growth decreased linearly or curvilinearly, least in ring-porous Quercus and deciduous conifers (by 10-40% per 100% defoliation), whereas growth of diffuse-porous hardwoods and evergreen conifers declined by 40-100%. Mortality increased exponentially with defoliation, most rapidly for evergreen conifers, then diffuse-porous, then ring-porous species and deciduous conifers (Larix). Goodness-of-fit for functional-group models was strong (R2c = 0.61-0.88), if lower than species-specific mixed-models (R2c = 0.77-0.93), providing useful alternatives when species data are lacking. These responses are consistent with functional differences in leaf longevity, wood growth phenology and NSC storage. When defoliator activity lags behind wood-growth, either because xylem-growth precedes budburst (Quercus) or defoliator activity peaks later (sawflies on Larix), impacts on annual wood-growth will always be lower. Wood-growth phenology of diffuse-porous species and evergreen conifers coincides with defoliation and responds more drastically, and lower axial NSC storage makes them

  3. Lycopodium: growth form, morphology, and sustainability of a non-timber forest product

    Treesearch

    Elizabeth A. Nauertz; John C. Zasada

    2001-01-01

    Several species of Lycopodium or clubmoss belong in the category of non-timber forest products and are often gathered for a variety of traditional uses. It is important to evaluate baseline information for these species, such as abundance and frequency of occurrence, before making any management decision. In addition, understanding the biology of the...

  4. Spatial models reveal the microclimatic buffering capacity of old-growth forests

    PubMed Central

    Frey, Sarah J. K.; Hadley, Adam S.; Johnson, Sherri L.; Schulze, Mark; Jones, Julia A.; Betts, Matthew G.

    2016-01-01

    Climate change is predicted to cause widespread declines in biodiversity, but these predictions are derived from coarse-resolution climate models applied at global scales. Such models lack the capacity to incorporate microclimate variability, which is critical to biodiversity microrefugia. In forested montane regions, microclimate is thought to be influenced by combined effects of elevation, microtopography, and vegetation, but their relative effects at fine spatial scales are poorly known. We used boosted regression trees to model the spatial distribution of fine-scale, under-canopy air temperatures in mountainous terrain. Spatial models predicted observed independent test data well (r = 0.87). As expected, elevation strongly predicted temperatures, but vegetation and microtopography also exerted critical effects. Old-growth vegetation characteristics, measured using LiDAR (light detection and ranging), appeared to have an insulating effect; maximum spring monthly temperatures decreased by 2.5°C across the observed gradient in old-growth structure. These cooling effects across a gradient in forest structure are of similar magnitude to 50-year forecasts of the Intergovernmental Panel on Climate Change and therefore have the potential to mitigate climate warming at local scales. Management strategies to conserve old-growth characteristics and to curb current rates of primary forest loss could maintain microrefugia, enhancing biodiversity persistence in mountainous systems under climate warming. PMID:27152339

  5. Spatial models reveal the microclimatic buffering capacity of old-growth forests.

    PubMed

    Frey, Sarah J K; Hadley, Adam S; Johnson, Sherri L; Schulze, Mark; Jones, Julia A; Betts, Matthew G

    2016-04-01

    Climate change is predicted to cause widespread declines in biodiversity, but these predictions are derived from coarse-resolution climate models applied at global scales. Such models lack the capacity to incorporate microclimate variability, which is critical to biodiversity microrefugia. In forested montane regions, microclimate is thought to be influenced by combined effects of elevation, microtopography, and vegetation, but their relative effects at fine spatial scales are poorly known. We used boosted regression trees to model the spatial distribution of fine-scale, under-canopy air temperatures in mountainous terrain. Spatial models predicted observed independent test data well (r = 0.87). As expected, elevation strongly predicted temperatures, but vegetation and microtopography also exerted critical effects. Old-growth vegetation characteristics, measured using LiDAR (light detection and ranging), appeared to have an insulating effect; maximum spring monthly temperatures decreased by 2.5°C across the observed gradient in old-growth structure. These cooling effects across a gradient in forest structure are of similar magnitude to 50-year forecasts of the Intergovernmental Panel on Climate Change and therefore have the potential to mitigate climate warming at local scales. Management strategies to conserve old-growth characteristics and to curb current rates of primary forest loss could maintain microrefugia, enhancing biodiversity persistence in mountainous systems under climate warming.

  6. OAK FOREST CARBON AND WATER SIMULATIONS: MODEL INTERCOMPARISONS AND EVALUATIONS AGAINST INDEPENDENT DATA

    SciTech Connect

    Hanson, Paul J; Amthor, Jeffrey S; Wullschleger, Stan D; Wilson, K.; Grant, Robert F.; Hartley, Anne; Hui, D.; HuntJr., E. Raymond; Johnson, Dale W.; Kimball, John S.; King, Anthony Wayne; Luo, Yiqi; McNulty, Steven G.; Sun, G.; Thornton, Peter; Wang, S.; Williams, M.; Baldocchi, D. D.; Cushman, Robert Michael

    2004-01-01

    Models represent our primary method for integration of small-scale, processlevel phenomena into a comprehensive description of forest-stand or ecosystem function. They also represent a key method for testing hypotheses about the response of forest ecosystems to multiple changing environmental conditions. This paper describes the evaluation of 13 stand-level models varying in their spatial, mechanistic, and temporal complexity for their ability to capture intra- and interannual components of the water and carbon cycle for an upland, oak-dominated forest of eastern Tennessee. Comparisons between model simulations and observations were conducted for hourly, daily, and annual time steps. Data for the comparisons were obtained from a wide range of methods including: eddy covariance, sapflow, chamber-based soil respiration, biometric estimates of stand-level net primary production and growth, and soil water content by time or frequency domain reflectometry. Response surfaces of carbon and water flux as a function of environmental drivers, and a variety of goodness-of-fit statistics (bias, absolute bias, and model efficiency) were used to judge model performance. A single model did not consistently perform the best at all time steps or for all variables considered. Intermodel comparisons showed good agreement for water cycle fluxes, but considerable disagreement among models for predicted carbon fluxes. The mean of all model outputs, however, was nearly always the best fit to the observations. Not surprisingly, models missing key forest components or processes, such as roots or modeled soil water content, were unable to provide accurate predictions of ecosystem responses to short-term drought phenomenon. Nevertheless, an inability to correctly capture short-term physiological processes under drought was not necessarily an indicator of poor annual water and carbon budget simulations. This is possible because droughts in the subject ecosystem were of short duration and

  7. Lumber grade and value performance of young-growth ponderosa pine logs at the Challenge Experimental Forest

    Treesearch

    Carl A. Newport; Elliot L. Amidon

    1961-01-01

    Old-growth timber is still the main source of ponderosa pine sawlogs in California, but the proportion of the annual cut from young-growth sawtimber is expected to rise rapidly in the future. The increasing significance of the young-growth resource is particularly apparent in the westside Sierra subregion, where the Challenge Experimental Forest is located. In this...

  8. An Individual-Tree Growth and Yield Prediction System for Even-Aged Natural Shortleaf Pine Forests

    Treesearch

    Thomas B. Lynch; Kenneth L. Hitch; Michael M. Huebschmann; Paul A. Murphy

    1999-01-01

    The development of a system of equations that model the growth and development of even-aged natural shortleaf (Pinus echinata Mill.) pine forests is described. The growth prediction system is a distance-independent individual-tree simulator containing equations that predict basal-area growth, survival, total and merchantable heights, and total and...

  9. Comprehensive evaluation system of intelligent urban growth

    NASA Astrophysics Data System (ADS)

    Li, Lian-Yan; Ren, Xiao-Bin

    2017-06-01

    With the rapid urbanization of the world, urban planning has become increasingly important and necessary to ensure people have access to equitable and sustainable homes, resources and jobs.This article is to talk about building an intelligent city evaluation system.First,using System Analysis Model(SAM) which concludes literature data analysis and stepwise regression analysis to describe intelligent growth scientifically and obtain the evaluation index. Then,using the improved entropy method to obtain the weight of the evaluation index.Afterwards, establishing a complete Smart Growth Comprehensive Evaluation Model(SGCEM).Finally,testing the correctness of the model.Choosing Otago(New Zealand )and Yumen(China) as research object by data mining and SGCEM model,then we get Yumen and Otago’s rational degree’s values are 0.3485 and 0.5376 respectively. It’s believed that the Otago’s smart level is higher,and it is found that the estimated value of rationality is consistent with the reality.

  10. The contribution of competition to tree mortality in old-growth coniferous forests

    USGS Publications Warehouse

    Das, A.; Battles, J.; Stephenson, N.L.; van Mantgem, P.J.

    2011-01-01

    Competition is a well-documented contributor to tree mortality in temperate forests, with numerous studies documenting a relationship between tree death and the competitive environment. Models frequently rely on competition as the only non-random mechanism affecting tree mortality. However, for mature forests, competition may cease to be the primary driver of mortality.We use a large, long-term dataset to study the importance of competition in determining tree mortality in old-growth forests on the western slope of the Sierra Nevada of California, U.S.A. We make use of the comparative spatial configuration of dead and live trees, changes in tree spatial pattern through time, and field assessments of contributors to an individual tree's death to quantify competitive effects.Competition was apparently a significant contributor to tree mortality in these forests. Trees that died tended to be in more competitive environments than trees that survived, and suppression frequently appeared as a factor contributing to mortality. On the other hand, based on spatial pattern analyses, only three of 14 plots demonstrated compelling evidence that competition was dominating mortality. Most of the rest of the plots fell within the expectation for random mortality, and three fit neither the random nor the competition model. These results suggest that while competition is often playing a significant role in tree mortality processes in these forests it only infrequently governs those processes. In addition, the field assessments indicated a substantial presence of biotic mortality agents in trees that died.While competition is almost certainly important, demographics in these forests cannot accurately be characterized without a better grasp of other mortality processes. In particular, we likely need a better understanding of biotic agents and their interactions with one another and with competition. ?? 2011.

  11. Atmospheric CO sub 2 concentrations within a mixed forest: Implications for seedling growth

    SciTech Connect

    Bazzaz, F.A.; Williams, W.E. )

    1991-02-01

    The authors studied carbon dioxide concentrations in a mixed deciduous forest in New England, US by making continuous measurements at 0.05, 0.2, 3, and 12m above the soil surface. The measurements began in early March and continued until the end of November 1985; therefore, they spanned the growing season and parts of the dormant seasons both before and afterwards. The data were compared with those from Mauna Loa Hawaii, which represent global atmospheric CO{sub 2} levels in the Northern Hemisphere. The results show strong seasonal and daily variations in CO{sub 2} concentrations at all heights in the forest. On average, during the growing season, CO{sub 2} levels were generally higher in the forest than in bulk air at Mauna Loa. The highest level of CO{sub 2} was found near the forest floor and the lowest at the 12-m level. Daily levels of CO{sub 2} were constant throughout the day in the dormant season and were the same for all heights in the forest. However, during the growing season, the Co{sub 2} concentrations were lowest during the middle of the day, especially at the 12m height. Thus, this study shows that the CO{sub 2} concentrations in the forest may be quite different than those in bulk air and that seedlings, saplings, and mature trees may experience different CO{sub 2} environments for which they may show different responses in photosynthesis, growth, and water use. Moreover, a tree may experience different CO{sub 2} environments as it grows towards the canopy, and different modules of an individual may also be growing in different CO{sub 2} atmospheres.

  12. Pattern and dynamics of biomass stock in old growth forests: The role of habitat and tree size

    NASA Astrophysics Data System (ADS)

    Yuan, Zuoqiang; Gazol, Antonio; Wang, Xugao; Lin, Fei; Ye, Ji; Zhang, Zhaochen; Suo, YanYan; Kuang, Xu; Wang, Yunyun; Jia, Shihong; Hao, Zhanqing

    2016-08-01

    Forest ecosystems play a fundamental role in the global carbon cycle. However, how stand-level changes in tree age and structure influence biomass stock and dynamics in old-growth forests is a question that remains unclear. In this study, we quantified the aboveground biomass (AGB) standing stock, the coarse woody productivity (CWP), and the change in biomass over ten years (2004-2014) in a 25 ha unmanaged broad-leaved Korean pine mixed forest in northeastern China. In addition, we quantified how AGB stock and change (tree growth, recruitment and mortality) estimations are influenced by the variation in habitat heterogeneity, tree size structure and subplot size. Our analysis indicated that Changbai forest had AGB of 265.4 Mg ha-1 in 2004, and gained1.36 Mg ha-1 y-1 between 2004 and 2014. Despite recruitment having better performance in nutrient rich habitat, we found that there is a directional tree growth trend independent of habitat heterogeneity for available nutrients in this old growth forest. The observed increases in AGB stock (∼70%) are mainly attributed to the growth of intermediate size trees (30-70 cm DBH), indicating that this forest is still reaching its mature stage. Meanwhile, we indicated that biomass loss due to mortality reduces living biomass, not increment, may be the primary factor to affect forest biomass dynamics in this area. Also, spatial variation in forest dynamics is large for small sizes (i.e. coefficient of variation in 20 × 20 m subplots is 53.2%), and more than 90 percent of the inherent variability of these coefficients was predicted by a simple model including plot size. Our result provides a mean by which to estimate within-plot variability at a local scale before inferring any directional change in forest dynamics at a regional scale, and information about the variability of forest structure and dynamics are fundamental to design effective sampling strategies in future study.

  13. Economic effects of reduced forest growth on the United States' forest economy and on Canadian-US lumber trade

    SciTech Connect

    Callaway, J.M.; Darwin, R.F.; Nesse, R.J.

    1986-08-01

    Reductions in tree growth rates may be related to increases in acid deposition and other man-made air pollutants over the last three decades. We review the evidence regarding reductions in forest growth and, using economic theory, show how physical changes can impact the production and purchasing decisions of buyers and sellers in timber and primary wood product markets. We then show how standard willingness-to-pay principles can be used to place monetary values on the physical damages caused by air pollution. In the second part of the study, we describe how information about changes in tree growth can be used in conjunction with existing inventory projection and timber market models to simulate the potential economic effects of acid deposition/air pollution in the United States. Two sets of simulations are conducted. The final part of the study presents the results of the simulations, quantifying the potential economic effects of acid deposition in the United States and to a limited extent, Canada. Estimates of the effects of reduced tree growth on the welfare of timber owners and the buyers and sellers of lumber and plywood in the United States are presented, along with information about changes in the welfare of lumber producers in Canada. Results suggest that if increases in Canadian stumpage fees (as a government response to transboundary pollution damage) are not too great, Canadian lumber producers and exporters may actually earn higher profits because of increased demand from the United States for Canadian lumber exports. 16 refs., 3 figs., 6 tabs.

  14. User group attitudes toward forest management treatments on the Shawnee National Forest: application of a photo-evaluation technique

    Treesearch

    Jonathan M. Cohen; Jean C. Mangun; Mae A. Davenport; Andrew D. Carver

    2008-01-01

    Diverse public opinions, competing management goals, and polarized interest groups combine with problems of scale to create a complex management arena for managers in the Central Hardwood Forest region. A mixed-methods approach that incorporated quantitative analysis of data from a photo evaluation-attitude scale survey instrument was used to assess attitudes toward...

  15. Who is the new sheriff in town regulating boreal forest growth?

    NASA Astrophysics Data System (ADS)

    Park Williams, A.; Xu, Chonggang; McDowell, Nate G.

    2011-12-01

    Climate change appears to be altering boreal forests. One recently observed symptom of these changes has been an apparent weakening of the positive relationship between high-latitude boreal tree growth and temperature at some sites (D'Arrigo et al 2008). This phenomenon is referred to as the 'divergence problem' or 'divergence effect' and is thought to reflect a non-linear relationship between temperature and tree growth, where recent warming has allowed other factors besides growing-season temperature to emerge as dominant regulators of annual growth rates. Figure 1 demonstrates this divergence phenomenon with records of tree-ring widths collected from 59 populations of white spruce in Alaska 1. Key tendencies among these populations include: (1) growth is most sensitive to temperature during relatively cold growing seasons (figure 1(a)), (2) populations at colder sites are more sensitive to temperature than those at warmer sites are (figure 1(a)), and (3) growth at warmer sites may respond negatively to increased temperature beyond some optimal growing-season temperature (figure 1(b)). Since temperature is rising rapidly at high latitudes, one interpretation of figures 1(a) and (b) is that warming has promoted increased growth at colder sites, but caused growth to plateau or slow at warmer sites. Corroborating this interpretation, satellite imagery and tree-ring data indicate increasing vegetation productivity near the forest-tundra boundary but declining productivity in warmer regions within forest interiors (e.g., Bunn and Goetz 2006, Beck and Goetz 2011, Beck et al 2011, Berner et al 2011). Will continued warming cause a northward migration of boreal forests, with mortality in the warmer, southern locations and expansion into the colder tundra? This question is difficult to answer because many factors besides temperature influence boreal forest dynamics. Widespread productivity declines within interior boreal forests appear to be related to warming

  16. User evaluation of campgrounds on two Michigan National Forests.

    Treesearch

    Robert C. Lucas

    1970-01-01

    Campground use on the Huron and Manistee National Forests in Michigan was studied in relation to resource characteristics, location, facilities provided, and visitor attitudes about the environment. Four factors in combination accounted for 69% of a variation in campground use per unit. Resource quality ratings made earlier as part of a nationwide Forest Service...

  17. EVALUATION OF FOREST CANOPY MODELS FOR ESTIMATING ISOPRENE EMISSIONS

    EPA Science Inventory

    During the summer of 1992, isoprene emissions were measured in a mixed deciduous forest near Oak Ridge, Tennessee. Measurements were aimed at the experimental scale-up of emissions from the leaf level to the forest canopy to the mixed layer. Results from the scale-up study are co...

  18. Geostatistical Evaluation of Natural Tree Regeneration of a Disturbed Forest

    Treesearch

    José Germán Flores Garnica; David Arturo Moreno Gonzalez; Juan de Dios Benavides Solorio

    2006-01-01

    The implementation of silvicultural strategies in a forest management has to guaranty forest sustainability, which is supported by an adequate regeneration. Therefore, quality and intensity of silvicultural practices is based on an accurate knowledge of the current spatial distribution of regeneration. At the same time, this regeneration is determined by the spatial...

  19. Systematic Evaluation of the "Forests in Schools" (SIS) Project.

    ERIC Educational Resources Information Center

    School Research Newsletter, 1985

    1985-01-01

    The purpose of an inquiry was to study the feasibility, content, mediation, and results of the Swedish "Forests in Schools" (SIS) project, an example of a link between schools and working life (the latter represented by forest enterprise in general). It also sought to describe and, if possible, explain the effects of the activities…

  20. Evaluation of Skylab (EREP) data for forest and rangeland surveys

    Treesearch

    Robert C. Aldrich

    1976-01-01

    Data products from the Skylab Earth Resources Experiment Package were examined monocularly or stereoscopically using a variety of magnifying interpretation devices. Land use, forest types, physiographic sites, and plant communities, as well as forest stress, were interpreted and mapped at sites in Georgia, South Dakota, and Colorado. Microdensitometric techniques and...

  1. Evaluating Multiple Imputation Models for the Southern Annual Forest Inventory

    Treesearch

    Gregory A. Reams; Joseph M. McCollum

    1999-01-01

    The USDA Forest Service's Southern Research Station is implementing an annualized forest survey in thirteen states. The sample design is a systematic sample of five interpenetrating grids (panels), where each panel is measured sequentially. For example, panel one information is collected in year one, and panel five in year five. The area representative and time...

  2. Evaluation of erosion control techniques on forest roads

    Treesearch

    Johnny M. Grace; Bob Rummer; Bryce J. Stokes; J. Wilhoit

    1998-01-01

    The cutslope and fillslope on a newly constructed forest road on the Talladega National Forest near Heflin, AL were treated with three erosion control techniques: wood excelsior erosion mat, native grass species, and exotic grass species. Bare soil plots were used as the experimental controls. Total sediment yield was measured during the period 21 September 1995 to 18...

  3. Evaluation of ERTS-1 data for forest and rangeland surveys

    Treesearch

    Robert C. Heller

    1975-01-01

    Tests used data gathered by the first Earth Resources Technology Satellite. Results on sites in Georgia, Colorado, and South Dakota indicated that ERTS enlargements, preferably color, would be useful to forest managers of large ownerships for broad area planning. Forest land was distinguished from nonforest land with 90 to 95 percent accuracy, in both...

  4. EVALUATION OF FOREST CANOPY MODELS FOR ESTIMATING ISOPRENE EMISSIONS

    EPA Science Inventory

    During the summer of 1992, isoprene emissions were measured in a mixed deciduous forest near Oak Ridge, Tennessee. Measurements were aimed at the experimental scale-up of emissions from the leaf level to the forest canopy to the mixed layer. Results from the scale-up study are co...

  5. Changes in plant species composition along an elevation gradient in an old-growth bottomland hardwood-Pinus taeda forest in southern Arkansas

    Treesearch

    Adrian G. Grell; Michael G. Shelton; Eric Heitzman

    2005-01-01

    Old-growth bottomland hardwood-Pinus taeda L. forests are rare in Arkansas, and the complex relationships between plant communities and environmental conditions have not been well described in these forests. To investigate these relationships, a digital elevation model was developed for a 16.2 ha old-growth bottomland hardwood-Pinus taeda forest in...

  6. The past and future of modeling forest dynamics: from growth and yield curves to forest landscape models

    Treesearch

    Stephen R. Shifley; Hong S. He; Heike Lischke; Wen J. Wang; Wenchi Jin; Eric J. Gustafson; Jonathan R. Thompson; Frank R. Thompson; William D. Dijak; Jian Yang

    2017-01-01

    Context. Quantitative models of forest dynamics have followed a progression toward methods with increased detail, complexity, and spatial extent. Objectives. We highlight milestones in the development of forest dynamics models and identify future research and application opportunities. Methods. We reviewed...

  7. Contingent valuation study of the value of reducing fire hazards to old-growth forests in the Pacific northwest. Forest Service research paper

    SciTech Connect

    Loomis, J.B.; Gonzalez-Caban, A.; Gregory, R.

    1996-07-01

    A contingent valuation methodology was applied to old-growth forests and critical habitat units for the Northern Spotted Owl in Oregon to esimate the economic value to the public in knowing that rare and unique ecosystems will be protected from fire for current and future generations. Generalizing to the whole state, the total annual willingness-to-pay of Oregon residents ranges from $49.6 to $99 million. In terms of old-growth forests protected from fire, the value is $28 per acre.

  8. Reduced aboveground tree growth associated with higher arbuscular mycorrhizal fungal diversity in tropical forest restoration.

    PubMed

    Holste, Ellen K; Holl, Karen D; Zahawi, Rakan A; Kobe, Richard K

    2016-10-01

    Establishing diverse mycorrhizal fungal communities is considered important for forest recovery, yet mycorrhizae may have complex effects on tree growth depending on the composition of fungal species present. In an effort to understand the role of mycorrhizal fungi community in forest restoration in southern Costa Rica, we sampled the arbuscular mycorrhizal fungal (AMF) community across eight sites that were planted with the same species (Inga edulis, Erythrina poeppigiana, Terminalia amazonia, and Vochysia guatemalensis) but varied twofold to fourfold in overall tree growth rates. The AMF community was measured in multiple ways: as percent colonization of host tree roots, by DNA isolation of the fungal species associated with the roots, and through spore density, volume, and identity in both the wet and dry seasons. Consistent with prior tropical restoration research, the majority of fungal species belonged to the genus Glomus and genus Acaulospora, accounting for more than half of the species and relative abundance found on trees roots and over 95% of spore density across all sites. Greater AMF diversity correlated with lower soil organic matter, carbon, and nitrogen concentrations and longer durations of prior pasture use across sites. Contrary to previous literature findings, AMF species diversity and spore densities were inversely related to tree growth, which may have arisen from trees facultatively increasing their associations with AMF in lower soil fertility sites. Changes to AMF community composition also may have led to variation in disturbance susceptibility, host tree nutrient acquisition, and tree growth. These results highlight the potential importance of fungal-tree-soil interactions in forest recovery and suggest that fungal community dynamics could have important implications for tree growth in disturbed soils.

  9. Tree growth rates in an Amazonian evergreen forest: seasonal patterns and correlations with leaf phenology

    NASA Astrophysics Data System (ADS)

    Wu, J.; Silva Campos, K.; Prohaska, N.; Ferreira, M. L.; Nelson, B. W.; Saleska, S. R.; da Silva, R.

    2014-12-01

    Metabolism and phenology of tropical forests significantly influence global dynamics of climate, carbon and water. However, there is still lack of mechanistic understanding of the controls on tropical forest metabolism, particularly at individual tree level. In this study, we are interested in investigating (1) what is the seasonal pattern of woody growth for tropical trees and (2) what is the mechanistic controls onwoody growth at individual level?To explore the above questions,we use two data sources from an evergreen tropical forest KM67 site (near Santarem, Brazil). They are: (1) image time series from a tower mounted RGB imaging system, with images recordedin10 minutes interval since October 2013.Images near local noon homogeneous diffuse lighting were selectedfor leaf phenologymonitoring; (2) ground based bi-weekly biometry survey (via dendrometry band technique) for 25 trees from random sampling since September 2013. 12 among 25 trees are within the tower mounted camera image view. Our preliminary resultsdemonstrate that 20 trees among 25 trees surveyed significantly increase woody growth (or "green up") in dry season. Our results also find thatamong those 20 trees, 12 trees reaches the maximum woody increment rate in late dry season with a mean DBH (Diameter at Breast Height) around 30 cm,while 8 trees reaching the maximum in the middle of wet season, with a mean DBH around 90 cm. This study,though limited in the sample size, mightprovide another line of evidence that Amazon rainforests "green up" in dry season. As for mechanistic controls on tropical tree woody control, we hypothesize both climate and leaf phenology control individual woody growth. We would like to link both camera based leaf phenology and climate data in the next to explorethe reason as to the pattern found in this study that bigger trees might have different seasonal growth pattern as smaller trees.

  10. Nitrogen limitation of growth and nutrient dynamics in a disturbed mangrove forest, Indian River Lagoon, Florida

    USGS Publications Warehouse

    Feller, Ilka C.; Whigham, D.F.; McKee, K.L.; Lovelock, C.E.

    2003-01-01

    The objectives of this study were to determine effects of nutrient enrichment on plant growth, nutrient dynamics, and photosynthesis in a disturbed mangrove forest in an abandoned mosquito impoundment in Florida. Impounding altered the hydrology and soil chemistry of the site. In 1997, we established a factorial experiment along a tree-height gradient with three zones, i.e., fringe, transition, dwarf, and three fertilizer treatment levels, i.e., nitrogen (N), phosphorus (P), control, in Mosquito Impoundment 23 on the eastern side of Indian River. Transects traversed the forest perpendicular to the shoreline, from a Rhizophora mangle-dominated fringe through an Avicennia germinans stand of intermediate height, and into a scrub or dwarf stand of A. germinans in the hinterland. Growth rates increased significantly in response to N fertilization. Our growth data indicated that this site is N-limited along the tree-height gradient. After 2 years of N addition, dwarf trees resembled vigorously growing saplings. Addition of N also affected internal dynamics of N and P and caused increases in rates of photosynthesis. These findings contrast with results for a R. mangle-dominated forest in Belize where the fringe is N-limited, but the dwarf zone is P-limited and the transition zone is co-limited by N and P. This study demonstrated that patterns of nutrient limitation in mangrove ecosystems are complex, that not all processes respond similarly to the same nutrient, and that similar habitats are not limited by the same nutrient when different mangrove forests are compared.

  11. Nitrogen limitation of growth and nutrient dynamics in a disturbed mangrove forest, Indian River Lagoon, Florida.

    PubMed

    Feller, Ilka C; Whigham, Dennis F; McKee, Karen L; Lovelock, Catherine E

    2003-02-01

    The objectives of this study were to determine effects of nutrient enrichment on plant growth, nutrient dynamics, and photosynthesis in a disturbed mangrove forest in an abandoned mosquito impoundment in Florida. Impounding altered the hydrology and soil chemistry of the site. In 1997, we established a factorial experiment along a tree-height gradient with three zones, i.e., fringe, transition, dwarf, and three fertilizer treatment levels, i.e., nitrogen (N), phosphorus (P), control, in Mosquito Impoundment 23 on the eastern side of Indian River. Transects traversed the forest perpendicular to the shoreline, from a Rhizophora mangle-dominated fringe through an Avicennia germinans stand of intermediate height, and into a scrub or dwarf stand of A. germinans in the hinterland. Growth rates increased significantly in response to N fertilization. Our growth data indicated that this site is N-limited along the tree-height gradient. After 2 years of N addition, dwarf trees resembled vigorously growing saplings. Addition of N also affected internal dynamics of N and P and caused increases in rates of photosynthesis. These findings contrast with results for a R. mangle-dominated forest in Belize where the fringe is N-limited, but the dwarf zone is P-limited and the transition zone is co-limited by N and P. This study demonstrated that patterns of nutrient limitation in mangrove ecosystems are complex, that not all processes respond similarly to the same nutrient, and that similar habitats are not limited by the same nutrient when different mangrove forests are compared.

  12. Trade-offs between seedling growth and survival in deciduous broadleaved trees in a temperate forest.

    PubMed

    Seiwa, Kenji

    2007-03-01

    In spatially heterogeneous environments, a trade-off between seedling survival and relative growth rate may promote the coexistence of plant species. In temperate forests, however, little support for this hypothesis has been found under field conditions, as compared with shade-house experiments. Performance trade-offs were examined over a large resource gradient in a temperate hardwood forest. The relationship between seedling survival and seedling relative growth rate in mass (RGR(M)) or height (RGR(H)) was examined at three levels of canopy cover (forest understorey, FU; small gap, SG; and large gap, LG) and at two microsites within each level of canopy cover (presence or absence of leaf litter) for five deciduous broad-leaved tree species with different seed sizes. Within each species, both RGR(M) and RGR(H) usually increased with increasing light levels (in the order FU < SG < LG), whereas little difference was observed based on the presence or absence of litter. Seedling survival in FU was negatively correlated with both RGR(M) and RGR(H) in both LG and SG. The trade-off between high-light growth and low-light survival was more evident in the relationship with LG as compared with SG. An intraspecific trade-off between survival and RGR was observed along environmental gradients in Acer mono, whereas seedlings of Betula platyphylla var. japonica survived and grew better in LG. The results presented here strongly support the idea of light gradient partitioning (i.e. species coexistence) in spatially heterogeneous light environments in temperate forests, and that further species diversity would be promoted by increased spatial heterogeneity. The intraspecific trade-off between survival and RGR in Acer suggests that it has broad habitat requirements, whereas Betula has narrow habitat requirements and specializes in high-light environments.

  13. [Dynamics of Amomum villosum growth and its fruit yield cultivated under tropical forests].

    PubMed

    Zheng, Zheng; Gan, Jianmin; Feng, Zhili; Meng, Ying

    2004-01-01

    Investigations on the dynamics of Amomum villosum growth and its fruit yield cultivated under tropical ravine rainforest and secondary forest at different elevations in Xishuangbanna showed that the yield of A. villosum was influenced by the site age, sun light level of understorey, and water stress in dry season. The fruit yield and mature plant density decreased with increasing age of the A. villosum site. The fruit yield increased with sun light level when the light level in understorey was under 35% of full sun light (P < 0.05). The fruit yield at the lower site by stream was significantly higher than that at upper site (P < 0.05). The yield difference between ravine rainforest and secondary forest was not significant. Planned cultivation of A. villosum in the secondary forest of the shifting cultivation land by ravine from 800-1000 m elevation instead of customary cultivation in the ravine rainforest, could not only resolve the problem of the effect of light deficiency in understorey and water stress in the dry season on A. villosum fruit yield, but also be useful to protect the tropical ravine rain forest.

  14. Amazon old-growth forest wind disturbance and the regional carbon balance

    NASA Astrophysics Data System (ADS)

    Chambers, J. Q.; Negron Juarez, R. I.; Marra, D. M.; Roberts, D. A.; Hurtt, G. C.; Lima, A.; Higuchi, N.

    2010-12-01

    Estimating the carbon balance of a landscape is challenging. A key problem is determining whether or not measurements made in plots are representative of the carbon state of a larger region. A key parameter for calculating landscape carbon balance is the return frequency of episodic disturbances. If disturbances are clustered and occur more frequently than the time required for biomass recovery, a spatial mixture of patches in different stages of recovery occurs. Under these shifting steady-state mosaic conditions, quantifying the mean state of ecosystem attributes such as carbon balance or tree species diversity is difficult. In this study, satellite remote sensing (Landsat) was coupled with field investigations to create ~25 year landscape-scale disturbance chronosequence for old-growth forest in the Central Amazon. The detected disturbances were caused by strong storms which resulted in tree mortality events ranging from small clusters of 7-10 downed trees, to large contiguous blowdowns larger than 30 ha in size. Using the chronosequence, a cumulative probability distribution function was developed, which followed a power law, and was used to parameterize a forest carbon balance model. Results demonstrate that for power law exponents less than about 2.0, the spatial scale at which forest carbon balance establishes is much larger than generally expected. Ultimately, an increase in wind disturbance frequency and/or intensity with a warming climate has the potential to cause a net loss of carbon from Amazon forests to the atmosphere.

  15. Carbon stocks of an old-growth forest and an anthropogenic peatland in southern Chile

    NASA Astrophysics Data System (ADS)

    Perez-Quezada, Jorge; Brito, Carla; Cabezas, Julian; Salvo, Patricia; Lemunao, Pedro; Flores, Ernesto; Valdés, Ariel; Fuentes, Juan Pablo; Galleguillos, Mauricio; Pérez, Cecilia

    2015-04-01

    The distribution of carbon in the different ecosystem stocks may change with direct human perturbation or climate change. We present a detailed description of the carbon stocks of an old-growth forest and an anthropogenic peatland (i.e., created by flooding, as a consequence of forest fires or logging). The study area was located in a private reserve in the Chiloé Island, southern Chile (41° 52' S, 73° 40' W). Sampling was done on plots separated 60 m from each other, in areas of approximately 30 ha for each ecosystem type. Total C was 1523 ± 117 Mg ha-1 in the forest and 130 ± 13.8 Mg ha-1 in the peatland, with 69.7% and 91.7% of this found belowground, respectively. In the forest, the necromass stock composed by logs and snags was high (183 Mg C ha-1), compared with the live-tree stock (264 Mg C ha-1) and with the C stored in the understory vegetation (14 Mg C ha-1). In the peatland, most of the C was stored in the most decomposed layer of peat, deeper in the ground. Because the anthropogenic peatland is experiencing a secondary succession, there is great potential to sequester back the C lost due to the perturbation. However, in most of the area where these ecosystems are found, the moss is being harvested for horticultural purposes.

  16. The synergistic effect in the Fe-Co bimetallic catalyst system for the growth of carbon nanotube forests

    SciTech Connect

    Hardeman, D.; Esconjauregui, S. Cartwright, R.; D'Arsié, L.; Robertson, J.; Bhardwaj, S.; Cepek, C.; Oakes, D.; Clark, J.; Ducati, C.

    2015-01-28

    We report the growth of multi-walled carbon nanotube forests employing an active-active bimetallic Fe-Co catalyst. Using this catalyst system, we observe a synergistic effect by which—in comparison to pure Fe or Co—the height of the forests increases significantly. The homogeneity in the as-grown nanotubes is also improved. By both energy dispersive spectroscopy and in-situ x-ray photoelectron spectroscopy, we show that the catalyst particles consist of Fe and Co, and this dramatically increases the growth rate of the tubes. Bimetallic catalysts are thus potentially useful for synthesising nanotube forests more efficiently.

  17. Can a Forest/Nonforest Change Map Improve the Precision of Forest Area, Volume, Growth, Removals, and Mortality Estimates?

    Treesearch

    Dale D. Gormanson; Mark H. Hansen; Ronald E. McRoberts

    2005-01-01

    In an extensive forest inventory, stratifications that use dual-date forest/nonforest classifications of Landsat Thematic Mapper data approximately 10 years apart are tested against similar classifications that use data from only one date. Alternative stratifications that further define edge strata as pixels adjacent to a forest/nonforest boundary are included in the...

  18. Tree growth-climate relationships in a forest-plot network on Mediterranean mountains.

    PubMed

    Fyllas, Nikolaos M; Christopoulou, Anastasia; Galanidis, Alexandros; Michelaki, Chrysanthi Z; Dimitrakopoulos, Panayiotis G; Fulé, Peter Z; Arianoutsou, Margarita

    2017-11-15

    In this study we analysed a novel tree-growth dataset, inferred from annual ring-width measurements, of 7 forest tree species from 12 mountain regions in Greece, in order to identify tree growth - climate relationships. The tree species of interest were: Abies cephalonica, Abies borisii-regis, Picea abies, Pinus nigra, Pinus sylvestris, Fagus sylvatica and Quercus frainetto growing across a gradient of climate conditions with mean annual temperature ranging from 5.7 to 12.6°C and total annual precipitation from 500 to 950mm. In total, 344 tree cores (one per tree) were analysed across a network of 20 study sites. We found that water availability during the summer period (May-August) was a strong predictor of interannual variation in tree growth for all study species. Across species and sites, annual tree growth was positively related to summer season precipitation (PSP). The responsiveness of annual growth to PSP was tightly related to species and site specific measurements of instantaneous photosynthetic water use efficiency (WUE), suggesting that the growth of species with efficient water use is more responsive to variations in precipitation during the dry months of the year. Our findings support the importance of water availability for the growth of mountainous Mediterranean tree species and highlight that future reductions in precipitation are likely to lead to reduced tree-growth under climate change conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Modelling and economic evaluation of forest biome shifts under climate change in Southwest Germany

    Treesearch

    Marc Hanewinkel; Susan Hummel; Dominik. Cullmann

    2010-01-01

    We evaluated the economic effects of a predicted shift from Norway spruce (Picea abies) to European beech (Fagus sylvatica) for a forest area of 1.3 million ha in southwest Germany. The shift was modelled with a generalized linear model (GLM) by using presence/absence data from the National Forest Inventory in Baden-Wurttemberg...

  20. Evaluating the forest stewardship program through a national survey of participants

    Treesearch

    J.D. Esseks; R.J. Moulton

    2000-01-01

    This paper reports findings from a national survey of 1,231 participants in the Forest Stewardship Program (FSP) of USDA's Forest Service. Launched in 1991, the FSP provides technical assistance through state forestry agencies to help landowners develop management plans for their non-industrial forestland. The survey allowed us to address five main evaluative...

  1. Evaluating regional differences in macroinvertebrate communities from forested depressional wetlands across eastern and central North America

    Treesearch

    Darold P. Batzer; Susan E. Dietz-Brantley; Barbara E. Taylor; Adrienne E. DeBiase

    2005-01-01

    Forested depressional wetlands are an important seasonal wetland type across eastern and central North America. Macroinvertebrates are crucial ecosystem components of most forested depressional wetlands, but community compositions can vary widely across the region. We evaluated variation in macroinvertebrate faunas across eastern and central North America using 5...

  2. Forest biomass supply for bioenergy in the southeast: Evaluating assessment scale

    Treesearch

    Christopher S. Galik; Robert C. Abt

    2012-01-01

    This study evaluates the potential impacts of expanded forest biomass use in the Southeast from present year through 2036, focusing on the forest supply, industrial, and GHG emissions implications of maximizing biomass co-firing with coal. We model demand scenarios at the state, subregional, and regional levels, and assess the influence of study scale on the observed...

  3. Looking for age-related growth decline in natural forests: unexpected biomass patterns from tree rings and simulated mortality

    USGS Publications Warehouse

    Foster, Jane R.; D'Amato, Anthony W.; Bradford, John B.

    2014-01-01

    Forest biomass growth is almost universally assumed to peak early in stand development, near canopy closure, after which it will plateau or decline. The chronosequence and plot remeasurement approaches used to establish the decline pattern suffer from limitations and coarse temporal detail. We combined annual tree ring measurements and mortality models to address two questions: first, how do assumptions about tree growth and mortality influence reconstructions of biomass growth? Second, under what circumstances does biomass production follow the model that peaks early, then declines? We integrated three stochastic mortality models with a census tree-ring data set from eight temperate forest types to reconstruct stand-level biomass increments (in Minnesota, USA). We compared growth patterns among mortality models, forest types and stands. Timing of peak biomass growth varied significantly among mortality models, peaking 20–30 years earlier when mortality was random with respect to tree growth and size, than when mortality favored slow-growing individuals. Random or u-shaped mortality (highest in small or large trees) produced peak growth 25–30 % higher than the surviving tree sample alone. Growth trends for even-aged, monospecific Pinus banksiana or Acer saccharum forests were similar to the early peak and decline expectation. However, we observed continually increasing biomass growth in older, low-productivity forests of Quercus rubra, Fraxinus nigra, and Thuja occidentalis. Tree-ring reconstructions estimated annual changes in live biomass growth and identified more diverse development patterns than previous methods. These detailed, long-term patterns of biomass development are crucial for detecting recent growth responses to global change and modeling future forest dynamics.

  4. Looking for age-related growth decline in natural forests: unexpected biomass patterns from tree rings and simulated mortality.

    PubMed

    Foster, Jane R; D'Amato, Anthony W; Bradford, John B

    2014-05-01

    Forest biomass growth is almost universally assumed to peak early in stand development, near canopy closure, after which it will plateau or decline. The chronosequence and plot remeasurement approaches used to establish the decline pattern suffer from limitations and coarse temporal detail. We combined annual tree ring measurements and mortality models to address two questions: first, how do assumptions about tree growth and mortality influence reconstructions of biomass growth? Second, under what circumstances does biomass production follow the model that peaks early, then declines? We integrated three stochastic mortality models with a census tree-ring data set from eight temperate forest types to reconstruct stand-level biomass increments (in Minnesota, USA). We compared growth patterns among mortality models, forest types and stands. Timing of peak biomass growth varied significantly among mortality models, peaking 20-30 years earlier when mortality was random with respect to tree growth and size, than when mortality favored slow-growing individuals. Random or u-shaped mortality (highest in small or large trees) produced peak growth 25-30% higher than the surviving tree sample alone. Growth trends for even-aged, monospecific Pinus banksiana or Acer saccharum forests were similar to the early peak and decline expectation. However, we observed continually increasing biomass growth in older, low-productivity forests of Quercus rubra, Fraxinus nigra, and Thuja occidentalis. Tree-ring reconstructions estimated annual changes in live biomass growth and identified more diverse development patterns than previous methods. These detailed, long-term patterns of biomass development are crucial for detecting recent growth responses to global change and modeling future forest dynamics.

  5. Light-driven growth in Amazon evergreen forests explained by seasonal variations of vertical canopy structure.

    PubMed

    Tang, Hao; Dubayah, Ralph

    2017-03-07

    Light-regime variability is an important limiting factor constraining tree growth in tropical forests. However, there is considerable debate about whether radiation-induced green-up during the dry season is real, or an apparent artifact of the remote-sensing techniques used to infer seasonal changes in canopy leaf area. Direct and widespread observations of vertical canopy structures that drive radiation regimes have been largely absent. Here we analyze seasonal dynamic patterns between the canopy and understory layers in Amazon evergreen forests using observations of vertical canopy structure from a spaceborne lidar. We discovered that net leaf flushing of the canopy layer mainly occurs in early dry season, and is followed by net abscission in late dry season that coincides with increasing leaf area of the understory layer. Our observations of understory development from lidar either weakly respond to or are not correlated to seasonal variations in precipitation or insolation, but are strongly related to the seasonal structural dynamics of the canopy layer. We hypothesize that understory growth is driven by increased light gaps caused by seasonal variations of the canopy. This light-regime variability that exists in both spatial and temporal domains can better reveal the drought-induced green-up phenomenon, which appears less obvious when treating the Amazon forests as a whole.

  6. Forest growth predicts soil N2O flux in Amazon basin

    NASA Astrophysics Data System (ADS)

    Van Haren, J. L.; Saleska, S. R.

    2012-12-01

    The high spatial and temporal variability of soil N2O fluxes, which process models have not managed to fully describe, has impeded their extrapolation from chamber to whole ecosystem. Our work, to determine the spatial and temporal variability of soil gas fluxes in the Tapajos National Forest in central Amazonia, Brazil, found that soil N2O fluxes are spatially and temporally highly correlated with overall forest growth. We hypothesize that the mechanism for this correlation is through belowground carbon allocation by trees. Trees are the main source of carbon to the soil microbial community and sugar addition experiments have demonstrated that soil communities are carbon limited. Extrapolation to a wide variety of forest inventory plots around the Amazon basin yields a basin wide N2O flux of 2.6 kg-N ha-1 y-1, higher than previous estimates ranging from 1.1 to 2.3 kg-N ha-1 y-1. We will discuss the application of a process based model (PnET-DNDC ) to our datasets examine the relationship between wood growth and N2O fluxes.

  7. Drought stress, growth, and nonstructural carbohydrate dynamics of pine trees in a semi-arid forest

    NASA Astrophysics Data System (ADS)

    Klein, Tamir; Yakir, Dan; Hoch, Günter

    2014-05-01

    • In trees under prolonged drought, both carbon uptake (C source) and growth (C sink) typically decrease. This correlation raises two important questions: (1) to what degree is tree growth limited by C availability; and (2) Is growth limited by concurrent C storage (e.g. as nonstructural carbohydrates, NSC). • To test the relationships between drought, growth, and C reserves, we monitored the changes in NSC levels and constructed stem growth chronologies of Pinus halepensis trees of three drought stress levels growing in Yatir forest, Israel, at the dry limit of forest existence. • Moderately stressed and stressed trees showed 37% and 21% of the stem growth of healthy trees in 2012; 71% and 31% of the sap flux density; and 79% and 66% of the final needle length. In spite of these large reductions, both starch and soluble sugars concentrations in branches of these trees were similar in all trees throughout the dry season (2-4% dry mass). At the same time the root starch concentrations of moderately stressed and stressed trees were 47% and 58% of that of healthy trees, but never below 2% d.m. • Our results suggest that the drought-induced growth reduction is associated with a general C shortage, rather than competition with concurrent C storage. The relatively small effect of drought stress level on NSC dynamics, the maintenance of a 2% d.m. starch, and the continued sap flow indicate that a whole-tree C starvation is not likely to occur in these trees growing at the edge of the desert. Special request: If the abstract is not accepted for presentation in this session, please consider for presentation in session BG2.11 Plant traits and biogeochemical cycles. Thank you.

  8. Geomorphological controls of Fraxinus excelsior growth and regeneration in floodplain forests.

    PubMed

    Dufour, S; Piégay, H

    2008-01-01

    Geomorphological changes can alter river hydrology and thus influence floodplain forest growth and regeneration. In this paper we quantify the effect of changes in channel elevation at the scale of four decades on hydrological conditions, overbank sediment deposits, water availability, and their impacts on common ash (Fraxinus excelsior) growth and recruitment in floodplain forests of the Ain River, France. Ash is a drought-sensitive species, and its regeneration is influenced by flood disturbance. We compared ash growth between 20 sample plots located in two contrasting geomorphological contexts using dendrochronological measurements: 11 along reaches degrading over the last 80 years and nine along stable or slightly aggrading reaches. In each context, half of the plots were located near the channel, and the remainder were within the floodplain. Ash regeneration was also quantified in each plot. This work showed that sites which undergo channel degradation are associated with less frequent overbank flows. Whereas there is no trend in either the climatic or stream flow timeseries over the last four decades, the growth patterns of ashes of these sites are significantly different as opposed to plots located in stable or aggraded reaches (bell shaped curve vs. constant increase in tree ring width). The variance through time due to climatic or stream flow control is masked by variance due to topographical changes. Currently plots located in degraded reaches show a lower ash growth (mean of 0.20 cm/yr vs. 0.34 cm/yr over the last decade) and less frequent ash seedling establishment. We have identified a hydrologic threshold for ash growth response when stand elevation values reach 1.5-2 m above the mean annual flow stage. Our results confirm that, at a many-decade timescale, changes in channel elevation must be considered in addition to other hydrological controls of hardwood species growth and recruitment.

  9. Simulating the Effects of Fire on Forests in the Russian Far East: Integrating a Fire Danger Model and the FAREAST Forest Growth Model Across a Complex Landscape

    NASA Astrophysics Data System (ADS)

    Sherman, N. J.; Loboda, T.; Sun, G.; Shugart, H. H.; Csiszar, I.

    2008-12-01

    The remaining natural habitat of the critically endangered Amur tiger (Panthera tigris altaica) and Amur leopard (Panthera pardus orientalis) is a vast, biologically and topographically diverse area in the Russian Far East (RFE). Although wildland fire is a natural component of ecosystem functioning in the RFE, severe or repeated fires frequently re-set the process of forest succession, which may take centuries to return the affected forests to the pre-fire state and thus significantly alters habitat quality and long-term availability. The frequency of severe fire events has increased over the last 25 years, leading to irreversible modifications of some parts of the species' habitats. Moreover, fire regimes are expected to continue to change toward more frequent and severe events under the influence of climate change. Here we present an approach to developing capabilities for a comprehensive assessment of potential Amur tiger and leopard habitat availability throughout the 21st century by integrating regionally parameterized fire danger and forest growth models. The FAREAST model is an individual, gap-based model that simulates forest growth in a single location and demonstrates temporally explicit forest succession leading to mature forests. Including spatially explicit information on probabilities of fire occurrence at 1 km resolution developed from the regionally specific remotely -sensed data-driven fire danger model improves our ability to provide realistic long-term projections of potential forest composition in the RFE. This work presents the first attempt to merge the FAREAST model with a fire disturbance model, to validate its outputs across a large region, and to compare it to remotely-sensed data products as well as in situ assessments of forest structure. We ran the FAREAST model at 1,000 randomly selected points within forested areas in the RFE. At each point, the model was calibrated for temperature, precipitation, slope, elevation, and fire

  10. Forecasting effects of SO/sub 2/ pollution on growth and succession in a western conifer forest

    SciTech Connect

    Kercher, J.R.; Axelrod, M.C.; Bingham, G.E.

    1980-06-18

    A simulator has been developed for the mixed conifer forest type of the Sierra Nevada, California to forecast the effects of SO/sub 2/ on forest growth and succession. The model simulates recruitment, growth, and death of each tree and is based on a northeastern USA simulator with extensive modifications. These modifications include the introduction of fire ecology, temporal seed crop patterns unique to the Sierra, and water stress. Pollutant stress is modeled as an effect on tree growth. The model simulates the shift from the ponderosa pine dominated forest type to the white fir dominated mixed conifer type as elevation increases from 5000 to 6000 ft. It also simulates the fire-suppression of white fir and the fire-climax of ponderosa pine. For a 10% growth reduction of ponderosa pine from pollutant stress and with growth reductions in other species as determined by their relative sensitivities, standing crops of ponderosa pine were reduced and white fir increased.

  11. Distribution and Characterization of Forested Wetlands in the Carolinas and Virginia

    Treesearch

    Mark J. Brown

    1995-01-01

    Recent forest inventories of North Carolina, South Carolina, and Virginia, included sampled for hydric soils, and wetland hydrology. Forest samples that met all 3 of these criteria were classified as forested wetland.This study characterizes wetland forests by extent, owner, age, forest type, physiography, volume, growth, and removals, and evaluates its contribution...

  12. The components of change for an annual forest inventory design

    Treesearch

    Francis A. Roesch

    2007-01-01

    The sample design of the USDA Forest Service's Forest Inventory and Analysis Program (FIA) with respect to a three-dimensional population (forest area X time) of tree attributes is formally defined and evaluated. The definitions for both the traditional components of growth, as presented by Meyer (1953, Forest Mensuration), and a discrete analog to the time...

  13. Evaluating forest management policies by parametric linear programing

    Treesearch

    Daniel I. Navon; Richard J. McConnen

    1967-01-01

    An analytical and simulation technique, parametric linear programing explores alternative conditions and devises an optimal management plan for each condition. Its application in solving policy-decision problems in the management of forest lands is illustrated in an example.

  14. Regenerating temperate forest mesocosms in elevated CO2: belowground growth and nitrogen cycling.

    PubMed

    Berntson, G M; Bazzaz, F A

    1997-12-01

    The response of temperate forest ecosystems to elevated atmospheric CO2 concentrations is important because these ecosystems represent a significant component of the global carbon cycle. Two important but not well understood processes which elevated CO2 may substantially alter in these systems are regeneration and nitrogen cycling. If elevated CO2 leads to changes in species composition in regenerating forest communities then the structure and function of these ecosystems may be affected. In most temperate forests, nitrogen appears to be a limiting nutrient. If elevated CO2 leads to reductions in nitrogen cycling through increased sequestration of nitrogen in plant biomass or reductions in mineralization rates, long-term forest productivity may be constrained. To study these processes, we established mesocosms of regenerating forest communities in controlled environments maintained at either ambient (375 ppm) or elevated (700 ppm) CO2 concentrations. Mesocosms were constructed from intact monoliths of organic forest soil. We maintained these mesocosms for 2 years without any external inputs of nitrogen and allowed the plants naturally present as seeds and rhizomes to regenerate. We used (15)N pool dilution techniques to quantify nitrogen fluxes within the mesocosms at the end of the 2 years. Elevated atmospheric CO2 concentration significantly affected a number of plant and soil processes in the experimental regenerating forest mesocosms. These changes included increases in total plant biomass production, plant C/N ratios, ectomycorrhizal colonization of tree fine roots, changes in tree fine root architecture, and decreases in plant NH4(+) uptake rates, gross NH4(+) mineralization rates, and gross NH4(+) consumption rates. In addition, there was a shift in the relative biomass contribution of the two dominant regenerating tree species; the proportion of total biomass contributed by white birch (Betula papyrifera) decreased and the proportion of total biomass

  15. Canopy gaps affect long-term patterns of tree growth and mortality in mature and old-growth forests in the Pacific Northwest

    Treesearch

    Andrew N. Gray; Thomas A. Spies; Robert J. Pabst

    2012-01-01

    Canopy gaps created by tree mortality can affect the speed and trajectory of vegetation growth. Species’ population dynamics, and spatial heterogeneity in mature forests. Most studies focus on plant development within gaps, yet gaps also affect the mortality and growth of surrounding trees, which influence shading and root encroachment into gaps and determine whether,...

  16. Effects of multiple environmental factors on CO2 emission and CH4 uptake from old-growth forest soils

    NASA Astrophysics Data System (ADS)

    Fang, H. J.; Yu, G. R.; Cheng, S. L.; Zhu, T. H.; Wang, Y. S.; Yan, J. H.; Wang, M.; Cao, M.; Zhou, M.

    2010-01-01

    To assess contribution of multiple environmental factors to carbon exchanges between the atmosphere and forest soils, four old-growth forests referred to as boreal coniferous forest, temperate needle-broadleaved mixed forest, subtropical evergreen broadleaved forest and tropical monsoon rain forest were selected along eastern China. In each old-growth forest, soil CO2 and CH4 fluxes were measured from 2003 to 2005 applying the static opaque chamber and gas chromatography technique. Soil temperature and moisture at the 10 cm depth were simultaneously measured with the greenhouse gas measurements. Inorganic N (NH4+-N and NO3--N) in the 0-10 cm was determined monthly. From north to south, annual mean CO2 emission ranged from 18.09 ± 0.22 to 35.40 ± 2.24 Mg CO2 ha-1 yr-1 and annual mean CH4 uptake ranged from 0.04 ± 0.11 to 5.15 ± 0.96 kg CH4 ha-1 yr-1 in the four old-growth forests. Soil CO2 flux in the old-growth forests was mainly driven by soil temperature, followed by soil moisture and NO3--N. Temperature sensitivity (Q10) of soil CO2 flux was lower at lower latitudes with high temperature and more precipitation, probably because of less soil organic carbon (SOC). Soil NO3- accumulation caused by environmental change was often accompanied by an increase in soil CO2 emission. In addition, soil CH4 uptake decreased with an increase in soil moisture. The response of soil CH4 flux to temperature was dependent upon the optimal value of soil temperature in each forest. Soil NH4+-N consumption tended to promote soil CH4 uptake in the old-growth forests, whereas soil NO3--N accumulation was not conducive to CH4 oxidation in anaerobic condition. These results indicate that soil mineral N dynamics largely affects the soil gas fluxes of CO2 and CH4 in the old-growth forests, along with climate conditions.

  17. Private forests, housing growth, and America’s water supply: A report from the Forests on the Edge and Forests to Faucets Projects

    Treesearch

    M. H. Mockrin; R. L. Lilja; E. Weidner; S. M. Stein; M. A. Carr

    2014-01-01

    America’s private forests provide a vast array of public goods and services, including abundant, clean surface water. Forest loss and development can affect water quality and quantity when forests are removed and impervious surfaces, such as paved roads, spread across the landscape. We rank watersheds across the conterminous United States according to the contributions...

  18. A framework for evaluating forest landscape model predictions using empirical data and knowledge

    Treesearch

    Wen J. Wang; Hong S. He; Martin A. Spetich; Stephen R. Shifley; Frank R. Thompson; William D. Dijak; Qia. Wang

    2014-01-01

    Evaluation of forest landscape model (FLM) predictions is indispensable to establish the credibility of predictions. We present a framework that evaluates short- and long-term FLM predictions at site and landscape scales. Site-scale evaluation is conducted through comparing raster cell-level predictions with inventory plot data whereas landscape-scale evaluation is...

  19. From Inspection to School Improvement? Evaluating the Accelerated Inspection Programme in Waltham Forest.

    ERIC Educational Resources Information Center

    Hopkins, David; Harris, Alma; Watling, Rob; Beresford, John

    1999-01-01

    Outlines the main findings from the evaluation of the Accelerated Inspection Programme (AIP) in Waltham Forest under three main phases (pre-inspection, inspection, and post inspection). Focuses on the relationship between inspection and school improvement. Discusses the recommendations. (CMK)

  20. Evaluating Anthropogenic Risk of Grassland and Forest Habitat Degradation Using Land-Cover Data

    EPA Science Inventory

    The effects of landscape context on habitat quality are receiving increased attention in conservation biology. The objective of this research is to demonstrate an approach to mapping and evaluating the anthropogenic risks of grassland and forest habitat degradation by examining ...

  1. Evaluating Anthropogenic Risk of Grassland and Forest Habitat Degradation Using Land-Cover Data

    EPA Science Inventory

    The effects of landscape context on habitat quality are receiving increased attention in conservation biology. The objective of this research is to demonstrate an approach to mapping and evaluating the anthropogenic risks of grassland and forest habitat degradation by examining ...

  2. From Inspection to School Improvement? Evaluating the Accelerated Inspection Programme in Waltham Forest.

    ERIC Educational Resources Information Center

    Hopkins, David; Harris, Alma; Watling, Rob; Beresford, John

    1999-01-01

    Outlines the main findings from the evaluation of the Accelerated Inspection Programme (AIP) in Waltham Forest under three main phases (pre-inspection, inspection, and post inspection). Focuses on the relationship between inspection and school improvement. Discusses the recommendations. (CMK)

  3. CVal: a spreadsheet tool to evaluate the direct benefits and costs of carbon sequestration contracts for managed forests

    Treesearch

    E.M. Bilek; Peter Becker; Tim. McAbee

    2009-01-01

    This documentation is meant to accompany CVal, a downloadable spreadsheet tool. CVal was constructed for foresters, other land management advisors, landowners, and carbon credit aggregators to evaluate the direct benefits and costs of entering into contracts for carbon sequestered in managed forests and forest plantations. CVal was designed to evaluate Exchange...

  4. Long-term growth and succession in restored and natural mangrove forests in southwestern Florida

    USGS Publications Warehouse

    Proffitt, C.E.; Devlin, D.J.

    2005-01-01

    We compared colonization, growth and succession from 1989 to 2000 in a restored mangrove site and in gap and closed canopy sites in a natural mangrove forest. The restored site was created in 1982 and planted with Rhizophora mangle (???2 m-2) propagules. By 1989, Laguncularia racemosa, with densities up to 12.9 tree m-2, was a dominant in all plots, although densities were greater at edge plots relative to inner plots, and near open water (west plots) relative to further inland (east plots), and in tall mangrove plots relative to scrub plots. Rhizophora mangle (1989 tree densities about 2 m-2) was a codominant in inner and scrub plots, while Avicennia germinans had the lowest densities (<1 tree m-2) in all plots. From 1989 to 2000 L. racemosa experienced reduced recruitment and apparent density-dependent mortality of canopy individuals in plots with high initial densities. Scrub plots experienced high rates of colonization by R. mangle and L. racemosa, rapid growth in height of all species (1989-1996), followed by a dieoff of L. racemosa in later years (1997-2000) as the canopy came to resemble that of tall mangrove plots. Colonization and growth rates were lower in gap and closed canopy regions of the natural forest relative to rates in the restored site. After 11 years, densities of L. racemosa were 10-20x lower and R. mangle slightly less in the gap relative to densities in tall mangrove plots in the restored site at the same age. Although the restored stand had converged with the natural forest by 2000 in terms of some factors such as species richness, vegetation cover, litterfall, and light penetration, trees were still much smaller and stem densities much higher. Full development of mature structure and ecological function will likely require decades more development. ?? Springer 2005.

  5. Early spring leaf out enhances growth and survival of saplings in a temperate deciduous forest.

    PubMed

    Augspurger, Carol K

    2008-05-01

    Saplings of many canopy tree species in winter deciduous forests receive the major portion of their light budget for their growing season prior to canopy closure in the spring. This period of high light may be critical for achieving a positive carbon (C) gain, thus contributing strongly to their growth and survival. This study of saplings of Aesculus glabra and Acer saccharum in Trelease Woods, Illinois, USA, tested this hypothesis experimentally by placing tents of shade cloth over saplings during their spring period of high light prior to canopy closure in three consecutive years. Leaf senescence began 16 days (year 0) and 60 days (year 1) earlier for shaded A. glabra saplings than control saplings. No change in senescence occurred for A. saccharum. The annual absolute growth in stem diameter of both species was negligible or negative for shaded saplings, but positive for control saplings. Only 7% of the shaded A. glabra saplings were alive after 2 years, while all control saplings survived for 3 years; only 20% of the shaded A. saccharum saplings survived for 3 years, while 73% of control saplings were alive after the same period. Early spring leaf out is a critical mechanism that allows the long-term persistence of saplings of these species in this winter deciduous forest. Studies and models of C gain, growth, and survival of saplings in deciduous forests may need to take into account their spring phenology because saplings of many species are actually "sun" individuals in the spring prior to their longer period in the summer shade.

  6. Lianas suppress seedling growth and survival of 14 tree species in a Panamanian tropical forest.

    PubMed

    Martínez-Izquierdo, Laura; García, María M; Powers, Jennifer S; Schnitzer, Stefan A

    2016-01-01

    Lianas are a common plant growth form in tropical forests, where they compete intensely with trees, decreasing tree recruitment, growth, and survival. If the detrimental effects of lianas vary significantly with tree species identity, as is often assumed, then lianas may influence tree species diversity and community composition. Furthermore, recent studies have shown that liana abundance and biomass are increasing relative to trees in neotropical forests, which will likely magnify the detrimental effects of lianas and may ultimately alter tree species diversity, relative abundances, and community composition. Few studies, however, have tested the responses of multiple tree species to the presence of lianas in robust, well-replicated experiments. We tested the hypotheses that lianas reduce tree seedling growth and survival, and that the effect of lianas varies with tree species identity. We used a large-scale liana removal experiment in Central Panama in which we planted 14 replicate seedlings of 14 different tree species that varied in shade tolerance in each of 16 80 x 80 m plots (eight liana-removal and eight unmanipulated controls; 3136 total seedlings). Over a nearly two-yr period, we found that tree seedlings survived 75% more, grew 300% taller, and had twice the aboveground biomass in liana-removal plots than seedlings in control plots, consistent with strong competition between lianas and tree seedlings. There were no significant differences in the response of tree species to liana competition (i.e., there was no species by treatment interaction), indicating that lianas had a similar negative effect on all 14 tree species. Furthermore, the effect of lianas did not vary with tree species shade tolerance classification, suggesting that the liana effect was not solely based on light. Based on these findings, recently observed increases in liana abundance in neotropical forests will substantially reduce tree regeneration, but will not significantly alter

  7. Environmental evaluation of the forest of MT Fuji, based on multiple satellite data

    NASA Astrophysics Data System (ADS)

    Shiosaka, K.; Konta, F.; Nishikawa, H.

    1994-03-01

    Evaluation of environmental roles of the forest of Mt. Fuji and estimation of deposition of sulfur dioxide on the leaves of Japanese cypress (Chamaecyparis obtusa) weere done based on satellite data. The evaluation suggests that artificial Japanese cypress forests, which occupy the largest area among vegetations of Mt. Fuji have problems concerning environmental role of storing of soil water, and that the result of the estimation indicates an uneven distribution of sulfur dioxide deposition.

  8. Reconstructed old-growth forest stand structure and composition of two stands on the Olympic Peninsula, Washington state

    Treesearch

    David H. Peter; Constance A. Harrington

    2010-01-01

    We reconstructed the stand structure and composition for two western Washington old-growth forest stands harvested around 1930 (named Fresca and Rail) from field and historical data. Both old-growth stands had a codominant or dominant 250-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) overstory with a few scattered older Douglas-fir....

  9. Remanat old-growth longleaf pine (Pinus palustris Mill.) savannas and forests of the southeastern USA: Status and threats

    Treesearch

    J. Moragan Varner; John S. Kush

    2004-01-01

    Old-growth savannas and forests dominated by longleaf pine (Pinus palustris Mill.) are of great conservation and research interest. Comprehensive inventories of old-growth communities, however, are lacking for most of longleaf pine's natural range. We searched the literature, interviewed regional experts, queried email discussion lists and...

  10. Interspecific divergence in foliar nutrient dynamics and stem growth in a temperate forest in response to chronic nitrogen inputs

    Treesearch

    Jeffrey D. May; Sarah Beth Burdette; Frank S. Gilliam; Mary Beth Adams

    2005-01-01

    We studied the effects of excessive nitrogen (N) fertilization on foliar nutrient dynamics and stem growth in three important tree species in a mixed-deciduous forest. Stem diameter growth, foliar N concentrations, nitrogen-phosphorus (NIP) ratios, and nutrient resorption were determined for Acer rubrum L. (ACRU), Liriodendron tulipifera L. (LITU), and Prunas serotina...

  11. Interactive effects of ozone and climate on tree growth and water use in a southern Appalachian forest in the USA

    Treesearch

    S.B. McLaughlin; S.D. Wullschleger; G. Sun

    2007-01-01

    A lack of data on responses of mature tree growth and water use to ambient ozone (O3) concentrations has been a major limitation in efforts to understand and model responses of forests to current and future changes in climate.Here, hourly to seasonal patterns of stem growth and sap flow velocity were...

  12. Earthworm influence on N availability and the growth of Cecropia schreberiana in tropical pasture and forest soils

    Treesearch

    G. Gonzalez; X. Zou

    1999-01-01

    This greenhouse study examines the effects of Pontoscolex corethrurus on the growth of Cecropia scheberiana in forest and pasture soils. Four treatments (0, 2, 20 worms and 0 worms + urea fertilizer) were applied to the soils to test if earthworms affect nitrogen availability, and consequently the growth of C. scheberiana. We recorded the number of seedlings, leaves,...

  13. Comparison of two energy forest growth models based on photosynthesis and nitrogen productivity

    SciTech Connect

    Eckersten, H.

    1985-05-01

    Two energy forest growth models are compared. The growth rate in the first model (nitrogen model) is determined by the amount of nitrogen in leaves and the nitrogen productivity. The growth rate in the second model (photosynthetic model) is mainly determined by the photosynthetic process in the leaves, which in turn depends on climatic conditions and nitrogen status of the leaves, and on allocation. When two parameters related to those of the nitrogen model are derived from the photosynthetic model and the significances of these sets of parameters compared, some suggestions for changes to both models so as to make them consistent can be made. Allocation of biomass between stems, leaves and roots is shown to be a function of the nitrogen concentration in the leaves whereas the net fraction of growth lost through growth respiration in leaves and roots and death of fine roots is almost independent of the nitrogen concentration in leaves. It is also shown that the nitrogen model yields too large an influence for increasing leaf biomass on growth rate to be explained only by the effect of increasing self-shading in a growing canopy. In steady state conditions the photosynthetic model has no maximum leaf biomass when not considering death of biomass, while in the nitrogen model leaf biomass is limited even without death of leaf biomass.

  14. Development and use of bounding functions in a forest growth model. [Pinus lambertiana; Calocedrus decurrens; Pseudotsuga menziesii; Abies concolor

    SciTech Connect

    Dolph, K.L. ); Dixon, G.E. )

    1993-01-01

    Erroneous predictions of forest growth and yield may result when computer simulation models use extrapolated data in repeated or long-term projections or if the models are used outside the range of data on which they were built. Bounding functions that limit the predicted diameter and height growth of individual trees to maximum observed values were developed to constrain these erroneous predictions in a forest growth and yield simulator. Species studied included sugar pine, incense-cedar, Douglas-fir, and California white fir.

  15. A method of evaluating forest site quality from soil, forest cover, and indicator plants

    Treesearch

    Marinus Westveld

    1952-01-01

    Foresters have overlooked too long the importance of soil as a factor in successful timber production. Greatest production in amount and quality of wood at the smallest cost can be attained by growing the tree species that are best suited to the climate and the soil of the locality in question.

  16. Evaluation of cleanings to maintain oak forests on the Allegheny National Forest

    Treesearch

    Kurt W. Gottschalk; Gary W. Miller; Robert L. White; Andrea Hille; Thomas M. Schuler

    2014-01-01

    Ten-year results for an administrative study on the Allegheny National Forest (ANF) that examined their cleaning (precommercial thinning) prescriptions and standards for success in maintaining oak (Quercus spp.) composition in young stands and maintaining oak stems in a competitive position are presented. Two studies were installed. One study was in...

  17. Bovine growth hormone: human food safety evaluation.

    PubMed

    Juskevich, J C; Guyer, C G

    1990-08-24

    Scientists in the Food and Drug Administration (FDA), after reviewing the scientific literature and evaluating studies conducted by pharmaceutical companies, have concluded that the use of recombinant bovine growth hormone (rbGH) in dairy cattle presents no increased health risk to consumers. Bovine GH is not biologically active in humans, and oral toxicity studies have demonstrated that rbGH is not orally active in rats, a species responsive to parenterally administered bGH. Recombinant bGH treatment produces an increase in the concentration of insulin-like growth factor-I (IGF-I) in cow's milk. However, oral toxicity studies have shown that bovine IGF-I lacks oral activity in rats. Additionally, the concentration of IGF-I in milk of rbGH-treated cows is within the normal physiological range found in human breast milk, and IGF-I is denatured under conditions used to process cow's milk for infant formula. On the basis of estimates of the amount of protein absorbed intact in humans and the concentration of IGF-I in cow's milk during rbGH treatment, biologically significant levels of intact IGF-I would not be absorbed.

  18. A regional-scale survey and analysis of forest growth and mortality as affected by site and stand factors and acidic deposition

    Treesearch

    Robert T. Brooks

    1994-01-01

    Regression analyses were used to identify factors most closely related to species growth and mortality on continuous forest survey plots in Pennsylvania. In 1985, 200 plots with two prior measurements (in the 1960s and 1970s) were selected and measured for a third time to determine periodic forest growth and mortality rates. Growth and mortality were analyzed for...

  19. Density, ages, and growth rates in old-growth and young-growth forests in coastal Oregon

    USGS Publications Warehouse

    Tappeiner, J. C.; Huffman, D.; Spies, T.; Bailey, John D.

    1997-01-01

    We studied the ages and diameter growth rates of trees in former Douglas-fir (Pseudotsuga menziesii (Mirb.)Franco) old-growth stands on 10 sites and compared them with young-growth stands (50-70 years old, regenerated after timber harvest) in the Coast Range of western Oregon. The diameters and diameter growth rates for the first 100 years of trees in the old-growth stands were significantly greater than those in the young-growth stands. Growth rates in the old stands were comparable with those from long-term studies of young stands in which density is about 100-120 trees/ha; often young-growth stand density is well over 500 trees/ha. Ages of large trees in the old stands ranged from 100 to 420 years; ages in young stands varied by only about 5 to 10 years. Apparently, regeneration of old-growth stands on these sites occurred over a prolonged period, and trees grew at low density with little self-thinning; in contrast, after timber harvest, young stands may develop with high density of trees with similar ages and considerable self-thinning. The results suggest that thinning may be needed in dense young stands where the management objective is to speed development of old-growth characteristics.

  20. Preliminary Survey on TRY Forest Traits and Growth Index Relations - New Challenges

    NASA Astrophysics Data System (ADS)

    Lyubenova, Mariyana; Kattge, Jens; van Bodegom, Peter; Chikalanov, Alexandre; Popova, Silvia; Zlateva, Plamena; Peteva, Simona

    2016-04-01

    Forest ecosystems provide critical ecosystem goods and services, including food, fodder, water, shelter, nutrient cycling, and cultural and recreational value. Forests also store carbon, provide habitat for a wide range of species and help alleviate land degradation and desertification. Thus they have a potentially significant role to play in climate change adaptation planning through maintaining ecosystem services and providing livelihood options. Therefore the study of forest traits is such an important issue not just for individual countries but for the planet as a whole. We need to know what functional relations between forest traits exactly can express TRY data base and haw it will be significant for the global modeling and IPBES. The study of the biodiversity characteristics at all levels and functional links between them is extremely important for the selection of key indicators for assessing biodiversity and ecosystem services for sustainable natural capital control. By comparing the available information in tree data bases: TRY, ITR (International Tree Ring) and SP-PAM the 42 tree species are selected for the traits analyses. The dependence between location characteristics (latitude, longitude, altitude, annual precipitation, annual temperature and soil type) and forest traits (specific leaf area, leaf weight ratio, wood density and growth index) is studied by by multiply regression analyses (RDA) using the statistical software package Canoco 4.5. The Pearson correlation coefficient (measure of linear correlation), Kendal rank correlation coefficient (non parametric measure of statistical dependence) and Spearman correlation coefficient (monotonic function relationship between two variables) are calculated for each pair of variables (indexes) and species. After analysis of above mentioned correlation coefficients the dimensional linear regression models, multidimensional linear and nonlinear regression models and multidimensional neural networks models are